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Atari ST Machine Specific Programming In Assembly
Chapter 11: Reconstructing Source Files
There are four legitimate sources for software. You can
purchase it, you can find it in magazines and books, you can
obtain it free as public domain or you can write it yourself.
Rarely will you be satisfied with any of it. Software that you
write is easy to alter because you have the source program.
Magazines and books usually provide source programs also. But
commercial and public domain software rarely, if ever, provide
that convenience. Altering programs for which you do not have
the source program is difficult, but not impossible. The task is
addressed in this chapter.
Learning From Other Programmers
If you are a new programmer, you may not realize the extent
to which experienced programmers study code produced by other
programmers. Of course, you will read in your references that
the only way to become a programmer is to write programs. To the
extent that writing programs is the only way in which you can
test your accumulation of knowledge about programming, that
statement is true. But it is not the whole story. I don't think
that I can be contradicted in the least when I say that you will
learn more about programming by studying programs produced by
other programmers than you ever will by working alone.
I am convinced of that because I am convinced that the
accumulation of knowledge and ability is regenerative, in the
electronic sense; that is, you learn a little from someone, apply
that to what you already know and use that combined knowledge to
generate new knowledge by your own initiative. Then you initiate
the cycle again by learning a little from someone else. I am not
striving to impress you with some radical new concept here; I am
constructing an argument concerning our debt to each other. The
conclusion of that argument is this: no one has ever learned
anything in solitude. We all learn from each other; therefore,
no one owns knowledge.
To the extent that every idea we can possibly conceive is
based on knowledge contributed by others, no idea, however
original can stand isolated; therefore, every item of work that
we produce is inherently public domain to some degree, whether we
admit the fact and regardless of our feelings about the matter.
But, because I want to illustrate the alteration of programs
produced by third party programmers; that is, programs not
produced by you nor me; I am forced to consider the feelings and
opinions of those programmers. I want to assure those
programmers and you that my intent is not to provide you with
assistance in pirating or plagiarizing their works. With no
malice intended, I only suggest that after you have purchased
software you have the right to study and alter it for your own
use if you choose to do so.
Furthermore, I suggest that, unless you attempt to
unethically exploit that right by selling or giving away copies
of either the original works or altered versions, the authors and
distributors of those works lose nothing by your study and
alterations, and, in fact, invite such activities merely by
making the material available. If I design a program or write a
book that I don't want you to study or alter, then I would be
foolish to publish either. Imagine the difficulties that
publishers would encounter if they were to try to prevent readers
from revealing the contents of magazines and books to those who
had not purchased and read them.
One final point, then we'll get down to the business at
hand. Software producers have asked that purchasers help to
protect them against piracy. I would be more sympathetic to that
plea if software developers, in turn, would help to protect
purchasers from software that does not perform as specified and
from expensive upgrades that introduce more errors than are
corrected; would write manuals for their products which actually
explained their use; and, finally, would provide the source code
so that users could correct the errors that seem beyond the
ability of the developers.
From Machine Language to Source Program
As a first example, I will step you through the process of
converting the machine language of PRG_8AR.ACC, introduced in
chapter 10, to a source program that may be altered and
assembled. The process involves the use of the AssemPro debugger
to provide disassembly and reassembly listings of the object
program. A few things to remember are:
1. The disassembly and reassembly AssemPro functions are
rather unforgiving. Any errors in usage are apt to cause
system crashes.
2. The listings provided by these functions are saved to the
directory from which the object program is loaded;
therefore, make sure that there is room before you begin.
3. Tiny programs produce large listings; large programs
produce extremely large listings. Examples will be
given.
4. The listings provided may contain characters that are not
printer compatible. These must be removed before
hardcopy is feasible.
During the machine language to assembly language conversion
process you may find it necessary to reload the object program in
order to single step through a portion of the program or to
obtain a fresh disassembly or reassembly listing. To insure that
the initial disassembly will be reproducible, you must be able to
load and reload the object program into a reproducible
environment. This means that all accessories and auto executed
programs contained in the system environment during initial
disassembly and/or reassembly must reside within the environment
during subsequent disassemblies and/or reassemblies.
Furthermore, no other programs should be executed before using
AssemPro to disassemble your object code. In fact, you may find
it necessary to cold boot the system between subsequent
disassemblies of one object program. The point is that you will
want the addresses shown on all listings to be identical;
therefore, you must insure that the object program will be loaded
into the same area of memory each time.
Begin by executing AssemPro. From the debugger, click on
the Execute program button. When the dialog box appears, click
on the OK button. From the file selector choose PRG_8AR.ACC.
Remember that the disassembly and reassembly listings will be
saved to the directory from which the program is loaded into the
debugger. Always allow sufficient room for the listings. For
example, PRG_8AR.ACC occupies only 1082 bytes of disk space, but
the disassembly listing requires 15,881 bytes and the reassembly
listing requires 17,074 bytes. At those ratios, a program that
requires 30K to 40K bytes of disk space may produce listings that
require as much as 500K bytes of space.
After the program has been loaded into the debugger, record
the program's start address. I will be using the values obtained
on my machine so that you will be able to observe the addresses
and calculations involved. The starting address for my example
is $B20F0. Click on the from address button. On the line which
appears at the bottom of the debugger screen, type the address of
the program's basepage. That address is Start address minus
$100; for this example it is $B20F0 - $100 = $B1FF0. Refer to
page 97 of the COMPUTE! TOS book and figure 11.1 during the
discussion to follow.
Figure 11.1. PRG_8AR.ACC's basepage as it appears in the
AssemPro debugger output window.
The longword stored at the first address of the basepage is
just the first address of the basepage itself; that is, $000B1FF0
is stored at $0B1FF0. The longword stored at basepage address +
8 ($0B1FF8) is the program's start address, $000B20F0. This
address is also called the text segment address. The longword
stored at basepage address + 12 ($0B1FFC) is the length of the
program's text segment, $000001E8. The longword stored at
basepage address + 16 ($0B2000) is the address of the program's
data segment, $000B22D8. The longword stored at basepage address
+ 20 ($0B2004) is the length of the program's data segment,
$0000021C. The longword stored at basepage address + 24
($0B2008) is the address of the program's bss segment, $000B24F4.
The longword stored at basepage address + 28 ($0B200C) is the
length of the program's bss segment, $00000552.
We want disassembly and reassembly listings that begin at
the program's start address, called the "from address" by
AssemPro, and terminate at the end of the longword following the
end of the program, called the "to address" by AssemPro. The
from address is given; it is $B20F0. The to address must be
calculated; it is the sum of the program's bss address plus the
length of the bss segment plus 4; that is, $B24F4 + $552 + $4 =
$B2A4A. Figure 11.2 illustrates the appearance of the
Disassembling dialog box just before the OK button is pressed;
figure 11.3 is the disassembly listing.
Note: there will be times when you will want to exclude a
program's bss section from a disassembly listing because of its
extreme length. In fact, the bss section reveals little
information beyond the amount of memory reserved for the data to
be stored there. Here I have simply omitted a large repetitious
segment of the listing.
Figure 11.2. Preparing the Disassembling dialog box.
From the Debugger menu, click on the Disassembling
option. Type the from address and the to address on the
appropriate lines. Click on File: and type the name to be
assigned to the listing file. On the heading line, type an
appropriate heading for the listing. Click on the continuous
button, and make sure that the hexadecimal button is
highlighted; click on the button if it is not. Finally, click
on the OK button. A flag will appear in place of the mouse
arrow, and it will remain until the disassembly is complete.
Figure 11.3. The disassembly listing.
PRG_8AR.ACC Disassembly
0B20F0 4FFA0954 LEA $B2A46(PC),A7
0B20F4 3F3C0000 MOVE.W #0,-(A7)
0B20F8 487A03E5 PEA $B24DF(PC)
0B20FC 3F3C003C MOVE.W #$3C,-(A7)
0B2100 4E41 TRAP #1
0B2102 508F ADDQ.L #8,A7
0B2104 33C0000B2530 MOVE.W D0,$B2530
0B210A 3F3A0424 MOVE.W $B2530(PC),-(A7)
0B210E 3F3C0001 MOVE.W #1,-(A7)
0B2112 3F3C0046 MOVE.W #$46,-(A7)
0B2116 4E41 TRAP #1
0B2118 5C8F ADDQ.L #6,A7
0B211A 363C00C8 MOVE.W #$C8,D3
0B211E 4BFA01B8 LEA $B22D8(PC),A5
0B2122 49FA03D0 LEA $B24F4(PC),A4
0B2126 47FA02E3 LEA $B240B(PC),A3
0B212A 610000DE BSR $B220A
0B212E 38BC000A MOVE.W #$A,(A4)
0B2132 397C00000002 MOVE.W #0,2(A4)
0B2138 397C00010004 MOVE.W #1,4(A4)
0B213E 397C00000006 MOVE.W #0,6(A4)
0B2144 397C00000008 MOVE.W #0,8(A4)
0B214A 61000178 BSR $B22C4
0B214E 610000BA BSR $B220A
0B2152 38BC0023 MOVE.W #$23,(A4)
0B2156 397C00010002 MOVE.W #1,2(A4)
0B215C 397C00010004 MOVE.W #1,4(A4)
0B2162 397C00010006 MOVE.W #1,6(A4)
0B2168 397C00000008 MOVE.W #0,8(A4)
0B216E 41FA038E LEA $B24FE(PC),A0
0B2172 33E80004000B2508 MOVE.W 4(A0),$B2508
0B217A 23FC000B24CB000B251C MOVE.L #$B24CB,$B251C
0B2184 6100013E BSR $B22C4
0B2188 33FA0388000B2544 MOVE.W $B2512(PC),$B2544
0B2190 61000078 BSR $B220A
0B2194 23FC000B2534000B251C MOVE.L #$B2534,$B251C
0B219E 38BC0017 MOVE.W #$17,(A4)
0B21A2 397C00000002 MOVE.W #0,2(A4)
0B21A8 397C00010004 MOVE.W #1,4(A4)
0B21AE 397C00010006 MOVE.W #1,6(A4)
0B21B4 397C00000008 MOVE.W #0,8(A4)
0B21BA 61000108 BSR $B22C4
0B21BE 41FA0374 LEA $B2534(PC),A0
0B21C2 0C500028 CMPI.W #$28,(A0)
0B21C6 66D6 BNE.S $B219E
0B21C8 30280008 MOVE.W 8(A0),D0
0B21CC B07A0376 CMP.W $B2544(PC),D0
0B21D0 66CC BNE.S $B219E
0B21D2 0C790005000B2532 CMPI.W #5,$B2532
0B21DA 67C2 BEQ.S $B219E
0B21DC 6100002C BSR $B220A
0B21E0 0C790005000B2532 CMPI.W #5,$B2532
0B21E8 6702 BEQ.S $B21EC
0B21EA 60B2 BRA.S $B219E
0B21EC 3F3A0342 MOVE.W $B2530(PC),-(A7)
0B21F0 3F3C003E MOVE.W #$3E,-(A7)
0B21F4 4E41 TRAP #1
0B21F6 588F ADDQ.L #4,A7
0B21F8 3F3C0001 MOVE.W #1,-(A7)
0B21FC 3F3A0332 MOVE.W $B2530(PC),-(A7)
0B2200 3F3C0046 MOVE.W #$46,-(A7)
0B2204 4E41 TRAP #1
0B2206 5C8F ADDQ.L #6,A7
0B2208 6094 BRA.S $B219E
0B220A 41FA020F LEA $B241B(PC),A0
0B220E 610000BC BSR $B22CC
0B2212 41FA00DC LEA $B22F0(PC),A0
0B2216 303A031A MOVE.W $B2532(PC),D0
0B221A E548 LSL.W #2,D0
0B221C 20700000 MOVEA.L 0(A0,D0.W),A0
0B2220 610000AA BSR $B22CC
0B2224 41FA0295 LEA $B24BB(PC),A0
0B2228 610000A2 BSR $B22CC
0B222C 41FA021D LEA $B244B(PC),A0
0B2230 6100009A BSR $B22CC
0B2234 41FA0285 LEA $B24BB(PC),A0
0B2238 61000092 BSR $B22CC
0B223C 41FA0245 LEA $B2483(PC),A0
0B2240 6100008A BSR $B22CC
0B2244 7E00 MOVEQ #0,D7
0B2246 7C04 MOVEQ #4,D6
0B2248 41FA02FC LEA $B2546(PC),A0
0B224C 2C4D MOVEA.L A5,A6
0B224E 3A3C0005 MOVE.W #5,D5
0B2252 303C000B MOVE.W #$B,D0
0B2256 10FC0020 MOVE.B #$20,(A0)+
0B225A 51C8FFFA DBRA D0,$B2256
0B225E 3007 MOVE.W D7,D0
0B2260 0200000F ANDI.B #$F,D0
0B2264 10330000 MOVE.B 0(A3,D0.W),D0
0B2268 10C0 MOVE.B D0,(A0)+
0B226A 10FC003A MOVE.B #$3A,(A0)+
0B226E 10FC0020 MOVE.B #$20,(A0)+
0B2272 3007 MOVE.W D7,D0
0B2274 E348 LSL.W #1,D0
0B2276 225E MOVEA.L (A6)+,A1
0B2278 30310000 MOVE.W 0(A1,D0.W),D0
0B227C 7403 MOVEQ #3,D2
0B227E E958 ROL.W #4,D0
0B2280 1200 MOVE.B D0,D1
0B2282 0201000F ANDI.B #$F,D1
0B2286 4881 EXT.W D1
0B2288 12331000 MOVE.B 0(A3,D1.W),D1
0B228C 10C1 MOVE.B D1,(A0)+
0B228E 51CAFFEE DBRA D2,$B227E
0B2292 10FC0020 MOVE.B #$20,(A0)+
0B2296 10FC0020 MOVE.B #$20,(A0)+
0B229A 51CDFFC2 DBRA D5,$B225E
0B229E 10BC0000 MOVE.B #0,(A0)
0B22A2 41FA02A2 LEA $B2546(PC),A0
0B22A6 61000024 BSR $B22CC
0B22AA 41FA016F LEA $B241B(PC),A0
0B22AE 6100001C BSR $B22CC
0B22B2 06470001 ADDI.W #1,D7
0B22B6 51CEFF90 DBRA D6,$B2248
0B22BA 06790001000B2532 ADDI.W #1,$B2532
0B22C2 4E75 RTS
0B22C4 220D MOVE.L A5,D1
0B22C6 3003 MOVE.W D3,D0
0B22C8 4E42 TRAP #2
0B22CA 4E75 RTS
0B22CC 2F08 MOVE.L A0,-(A7)
0B22CE 3F3C0009 MOVE.W #9,-(A7)
0B22D2 4E41 TRAP #1
0B22D4 5C8F ADDQ.L #6,A7
0B22D6 4E75 RTS
0B22D8 000B DC.W $B
0B22DA 24F4000B MOVE.L $B(A4,D0.W),(A2)+
0B22DE 24FE MOVE.L SR,(A2)+
0B22E0 000B DC.W $B
0B22E2 2508 MOVE.L A0,-(A2)
0B22E4 000B DC.W $B
0B22E6 2512 MOVE.L (A2),-(A2)
0B22E8 000B DC.W $B
0B22EA 251C MOVE.L (A4)+,-(A2)
0B22EC 000B DC.W $B
0B22EE 2526 MOVE.L -(A6),-(A2)
0B22F0 000B DC.W $B
0B22F2 2304 MOVE.L D4,-(A1)
0B22F4 000B DC.W $B
0B22F6 2329000B MOVE.L $B(A1),-(A1)
0B22FA 2363000B MOVE.L -(A3),$B(A1)
0B22FE 239E000B MOVE.L (A6)+,$B(A1,D0.W)
0B2302 23D80D0A5445 MOVE.L (A0)+,$A5445
0B2308 5354 SUBQ.W #1,(A4)
0B230A 2050 MOVEA.L (A0),A0
0B230C 4F49 DC.W $4F49 ;"OI"
0B230E 4E542030 LINK A4,#$2030
0B2312 3A20 MOVE.W -(A0),D5
0B2314 4265 CLR.W -(A5)
0B2316 666F BNE.S $B2387
0B2318 7265 MOVEQ #$65,D1
0B231A 2061 MOVEA.L -(A1),A0
0B231C 7070 MOVEQ #$70,D0
0B231E 6C5F BGE.S $B237F
0B2320 696E BVS.S $B2390
0B2322 6974 BVS.S $B2398
0B2324 0D0A0D0A MOVEP.W $D0A(A2),D6
0B2328 000D DC.W $D
0B232A 0A544553 EORI.W #$4553,(A4)
0B232E 5420 ADDQ.B #2,-(A0)
0B2330 504F ADDQ.W #8,A7
0B2332 494E DC.W $494E ;"IN"
0B2334 5420 ADDQ.B #2,-(A0)
0B2336 313A2041 MOVE.W $B4379(PC),-(A0)
0B233A 6674 BNE.S $B23B0
0B233C 6572 BCS.S $B23B0
0B233E 2061 MOVEA.L -(A1),A0
0B2340 7070 MOVEQ #$70,D0
0B2342 6C5F BGE.S $B23A3
0B2344 696E BVS.S $B23B4
0B2346 6974 BVS.S $B23BC
0B2348 2C20 MOVE.L -(A0),D6
0B234A 6265 BHI.S $B23B1
0B234C 666F BNE.S $B23BD
0B234E 7265 MOVEQ #$65,D1
0B2350 206D656E MOVEA.L $656E(A5),A0
0B2354 755F DC.W $755F ;"u_"
0B2356 7265 MOVEQ #$65,D1
0B2358 6769 BEQ.S $B23C3
0B235A 7374 DC.W $7374 ;"st"
0B235C 6572 BCS.S $B23D0
0B235E 0D0A0D0A MOVEP.W $D0A(A2),D6
0B2362 000D DC.W $D
0B2364 0A544553 EORI.W #$4553,(A4)
0B2368 5420 ADDQ.B #2,-(A0)
0B236A 504F ADDQ.W #8,A7
0B236C 494E DC.W $494E ;"IN"
0B236E 5420 ADDQ.B #2,-(A0)
0B2370 323A2041 MOVE.W $B43B3(PC),D1
0B2374 6674 BNE.S $B23EA
0B2376 6572 BCS.S $B23EA
0B2378 206D656E MOVEA.L $656E(A5),A0
0B237C 755F DC.W $755F ;"u_"
0B237E 7265 MOVEQ #$65,D1
0B2380 6769 BEQ.S $B23EB
0B2382 7374 DC.W $7374 ;"st"
0B2384 6572 BCS.S $B23F8
0B2386 2C20 MOVE.L -(A0),D6
0B2388 6265 BHI.S $B23EF
0B238A 666F BNE.S $B23FB
0B238C 7265 MOVEQ #$65,D1
0B238E 2065 MOVEA.L -(A5),A0
0B2390 766E MOVEQ #$6E,D3
0B2392 745F MOVEQ #$5F,D2
0B2394 6D65 BLT.S $B23FB
0B2396 7361 DC.W $7361 ;"sa"
0B2398 670D BEQ.S $B23A7
0B239A 0A0D DC.W $A0D
0B239C 0A000D0A EORI.B #$A,D0
0B23A0 5445 ADDQ.W #2,D5
0B23A2 5354 SUBQ.W #1,(A4)
0B23A4 2050 MOVEA.L (A0),A0
0B23A6 4F49 DC.W $4F49 ;"OI"
0B23A8 4E542033 LINK A4,#$2033
0B23AC 3A20 MOVE.W -(A0),D5
0B23AE 496E DC.W $496E ;"In"
0B23B0 206D6573 MOVEA.L $6573(A5),A0
0B23B4 7361 DC.W $7361 ;"sa"
0B23B6 6765 BEQ.S $B241D
0B23B8 2068616E MOVEA.L $616E(A0),A0
0B23BC 646C BCC.S $B242A
0B23BE 6572 BCS.S $B2432
0B23C0 2C20 MOVE.L -(A0),D6
0B23C2 6265 BHI.S $B2429
0B23C4 666F BNE.S $B2435
0B23C6 7265 MOVEQ #$65,D1
0B23C8 2065 MOVEA.L -(A5),A0
0B23CA 766E MOVEQ #$6E,D3
0B23CC 745F MOVEQ #$5F,D2
0B23CE 6D65 BLT.S $B2435
0B23D0 7361 DC.W $7361 ;"sa"
0B23D2 670D BEQ.S $B23E1
0B23D4 0A0D DC.W $A0D
0B23D6 0A000D0A EORI.B #$A,D0
0B23DA 5445 ADDQ.W #2,D5
0B23DC 5354 SUBQ.W #1,(A4)
0B23DE 2050 MOVEA.L (A0),A0
0B23E0 4F49 DC.W $4F49 ;"OI"
0B23E2 4E542034 LINK A4,#$2034
0B23E6 3A20 MOVE.W -(A0),D5
0B23E8 496E DC.W $496E ;"In"
0B23EA 206D6573 MOVEA.L $6573(A5),A0
0B23EE 7361 DC.W $7361 ;"sa"
0B23F0 6765 BEQ.S $B2457
0B23F2 2068616E MOVEA.L $616E(A0),A0
0B23F6 646C BCC.S $B2464
0B23F8 6572 BCS.S $B246C
0B23FA 2073 DC.W $2073 ;" s"
0B23FC 6563 BCS.S $B2461
0B23FE 6F6E BLE.S $B246E
0B2400 6420 BCC.S $B2422
0B2402 7469 MOVEQ #$69,D2
0B2404 6D65 BLT.S $B246B
0B2406 0D0A0D0A MOVEP.W $D0A(A2),D6
0B240A 0030 DC.W $30
0B240C 3132 DC.W $3132 ;"12"
0B240E 3334 DC.W $3334 ;"34"
0B2410 3536 DC.W $3536 ;"56"
0B2412 37383941 MOVE.W $3941,-(A3)
0B2416 4243 CLR.W D3
0B2418 4445 NEG.W D5
0B241A 460D DC.W $460D
0B241C 0A002020 EORI.B #$20,D0
0B2420 2020 MOVE.L -(A0),D0
0B2422 2020 MOVE.L -(A0),D0
0B2424 2020 MOVE.L -(A0),D0
0B2426 2020 MOVE.L -(A0),D0
0B2428 2020 MOVE.L -(A0),D0
0B242A 2020 MOVE.L -(A0),D0
0B242C 2020 MOVE.L -(A0),D0
0B242E 2020 MOVE.L -(A0),D0
0B2430 2020 MOVE.L -(A0),D0
0B2432 2020 MOVE.L -(A0),D0
0B2434 2020 MOVE.L -(A0),D0
0B2436 2020 MOVE.L -(A0),D0
0B2438 2020 MOVE.L -(A0),D0
0B243A 2020 MOVE.L -(A0),D0
0B243C 2020 MOVE.L -(A0),D0
0B243E 4145 DC.W $4145 ;"AE"
0B2440 5320 SUBQ.B #1,-(A0)
0B2442 4152 DC.W $4152 ;"AR"
0B2444 5241 ADDQ.W #1,D1
0B2446 5953 SUBQ.W #4,(A3)
0B2448 0D0A0043 MOVEP.W $43(A2),D6
0B244C 4F4E DC.W $4F4E ;"ON"
0B244E 5452 ADDQ.W #2,(A2)
0B2450 4F4C DC.W $4F4C ;"OL"
0B2452 2020 MOVE.L -(A0),D0
0B2454 474C DC.W $474C ;"GL"
0B2456 4F42 DC.W $4F42 ;"OB"
0B2458 414C DC.W $414C ;"AL"
0B245A 2020 MOVE.L -(A0),D0
0B245C 2049 MOVEA.L A1,A0
0B245E 4E545F49 LINK A4,#$5F49
0B2462 4E20 DC.W $4E20 ;"N "
0B2464 2020 MOVE.L -(A0),D0
0B2466 494E DC.W $494E ;"IN"
0B2468 545F ADDQ.W #2,(A7)+
0B246A 4F55 DC.W $4F55 ;"OU"
0B246C 5420 ADDQ.B #2,-(A0)
0B246E 2041 MOVEA.L D1,A0
0B2470 4444 NEG.W D4
0B2472 525F ADDQ.W #1,(A7)+
0B2474 494E DC.W $494E ;"IN"
0B2476 2020 MOVE.L -(A0),D0
0B2478 4144 DC.W $4144 ;"AD"
0B247A 4452 NEG.W (A2)
0B247C 5F4F SUBQ.W #7,A7
0B247E 5554 SUBQ.W #2,(A4)
0B2480 0D0A002D MOVEP.W $2D(A2),D6
0B2484 2D2D2D2D MOVE.L $2D2D(A5),-(A6)
0B2488 2D2D2020 MOVE.L $2020(A5),-(A6)
0B248C 2D2D2D2D MOVE.L $2D2D(A5),-(A6)
0B2490 2D2D2D20 MOVE.L $2D20(A5),-(A6)
0B2494 202D2D2D MOVE.L $2D2D(A5),D0
0B2498 2D2D2D2D MOVE.L $2D2D(A5),-(A6)
0B249C 2020 MOVE.L -(A0),D0
0B249E 2D2D2D2D MOVE.L $2D2D(A5),-(A6)
0B24A2 2D2D2D20 MOVE.L $2D20(A5),-(A6)
0B24A6 202D2D2D MOVE.L $2D2D(A5),D0
0B24AA 2D2D2D2D MOVE.L $2D2D(A5),-(A6)
0B24AE 2020 MOVE.L -(A0),D0
0B24B0 2D2D2D2D MOVE.L $2D2D(A5),-(A6)
0B24B4 2D2D2D2D MOVE.L $2D2D(A5),-(A6)
0B24B8 0D0A0020 MOVEP.W $20(A2),D6
0B24BC 2020 MOVE.L -(A0),D0
0B24BE 2020 MOVE.L -(A0),D0
0B24C0 2020 MOVE.L -(A0),D0
0B24C2 2020 MOVE.L -(A0),D0
0B24C4 2020 MOVE.L -(A0),D0
0B24C6 2000 MOVE.L D0,D0
0B24C8 2020 MOVE.L -(A0),D0
0B24CA 00202041 ORI.B #$41,-(A0)
0B24CE 6363 BLS.S $B2533
0B24D0 6573 BCS.S $B2545
0B24D2 736F DC.W $736F ;"so"
0B24D4 7279 MOVEQ #$79,D1
0B24D6 2041 MOVEA.L D1,A0
0B24D8 7272 MOVEQ #$72,D1
0B24DA 6179 BSR.S $B2555
0B24DC 7320 DC.W $7320 ;"s "
0B24DE 00453A5C ORI.W #$3A5C,D5
0B24E2 5052 ADDQ.W #8,(A2)
0B24E4 475F DC.W $475F ;"G_"
0B24E6 385C MOVEA.W (A4)+,A4
0B24E8 5052 ADDQ.W #8,(A2)
0B24EA 475F DC.W $475F ;"G_"
0B24EC 3841 MOVEA.W D1,A4
0B24EE 522E4441 ADDQ.B #1,$4441(A6)
0B24F2 5400 ADDQ.B #2,D0
0B24F4 00000000 ORI.B #0,D0
The section containing addresses 0B24F8 - 0B2A40 omitted.
0B2A44 00000000 ORI.B #0,D0
0B2A48 00000000 ORI.B #0,D0
When the mouse arrow appears following disassembly, choose
the Reassembling option from the debugger menu. Click on File:
and change the extension from DSM to ASM. Click on the OK
button. When the More Start Addresses dialog box appears, click
on the Quit button. A flag will appear in place of the mouse
arrow until the reassembly is complete. Figure 11.4 illustrates
the appearance of the Reassembling dialog box just before you
press the OK button; figure 11.5 is the reassembly listing,
somewhat abbreviated, with the repetitious portion omitted.
Figure 11.4. Preparing the reassembling dialog box.
Preparing the File for Printing
Before I place the reassembly listing in this document, I
must remove certain characters that are not compatible with my
printer. These are the characters following the semicolons on
the lines 148 through 169. With TEMPUS, I remove the unwanted
character groups by typing ;* on the Search below string: line,
and by typing a blank space on the ... and replace by following
line. I choose the whole text for the search region; start
search at cursor, with the cursor at the semicolon of the first
group; and selectable for the quantity option. When the START
button is pressed, the cursor advances to each semicolon in turn,
stopping to permit a selection from the Search & Replace
selection dialog box. I can then choose YES, NO or CANCEL as
desired.
Figure 11.5. The reassembly listing.
1: K00001=0
2: K00003=$3C
3: K00004=1
4: K00006=$46
5: K00007=$C8
6: K0000C=$A
7: K0000D=2
8: K0000E=4
9: K0000F=6
10: K00010=8
11: K00012=$23
12: K0001A=$17
13: K0001B=$28
14: K0001D=5
15: K00020=$3E
16: K00028=$B
17: K00029=$20
18: K0002B=$F
19: K0002C=$3A
20: K0002D=3
21: K00031=9
22: LEA L00000(PC),A7
23: MOVE.W #K00001,-(A7)
24: PEA L00002+1(PC)
25: MOVE.W #K00003,-(A7)
26: TRAP #K00004
27: ADDQ.L #8,A7
28: MOVE.W D0,L00005
29: MOVE.W L00005(PC),-(A7)
30: MOVE.W #K00004,-(A7)
31: MOVE.W #K00006,-(A7)
32: TRAP #K00004
33: ADDQ.L #6,A7
34: MOVE.W #K00007,D3
35: LEA L00008(PC),A5
36: LEA L00009(PC),A4
37: LEA L0000A+1(PC),A3
38: BSR L0000B
39: MOVE.W #K0000C,(A4)
40: MOVE.W #K00001,K0000D(A4)
41: MOVE.W #K00004,K0000E(A4)
42: MOVE.W #K00001,K0000F(A4)
43: MOVE.W #K00001,K00010(A4)
44: BSR L00011
45: BSR L0000B
46: MOVE.W #K00012,(A4)
47: MOVE.W #K00004,K0000D(A4)
48: MOVE.W #K00004,K0000E(A4)
49: MOVE.W #K00004,K0000F(A4)
50: MOVE.W #K00001,K00010(A4)
51: LEA L00013(PC),A0
52: MOVE.W K0000E(A0),L00014
53: MOVE.L #L00015+1,L00016
54: BSR L00011
55: MOVE.W L00017(PC),L00018
56: BSR L0000B
57: MOVE.L #L00019,L00016
58: L0001C:MOVE.W #K0001A,(A4)
59: MOVE.W #K00001,K0000D(A4)
60: MOVE.W #K00004,K0000E(A4)
61: MOVE.W #K00004,K0000F(A4)
62: MOVE.W #K00001,K00010(A4)
63: BSR L00011
64: LEA L00019(PC),A0
65: CMPI.W #K0001B,(A0)
66: BNE.S L0001C
67: MOVE.W K00010(A0),D0
68: CMP.W L00018(PC),D0
69: BNE.S L0001C
70: CMPI.W #K0001D,L0001E
71: BEQ.S L0001C
72: BSR L0000B
73: CMPI.W #K0001D,L0001E
74: BEQ.S L0001F
75: BRA.S L0001C
76: L0001F:MOVE.W L00005(PC),-(A7)
77: MOVE.W #K00020,-(A7)
78: TRAP #K00004
79: ADDQ.L #4,A7
80: MOVE.W #K00004,-(A7)
81: MOVE.W L00005(PC),-(A7)
82: MOVE.W #K00006,-(A7)
83: TRAP #K00004
84: ADDQ.L #6,A7
85: BRA.S L0001C
86: L0000B:LEA L00021+1(PC),A0
87: BSR L00022
88: LEA L00023(PC),A0
89: MOVE.W L0001E(PC),D0
90: LSL.W #K0000D,D0
91: MOVEA.L K00001(A0,D0.W),A0
92: BSR L00022
93: LEA L00024+1(PC),A0
94: BSR L00022
95: LEA L00025+1(PC),A0
96: BSR L00022
97: LEA L00024+1(PC),A0
98: BSR L00022
99: LEA L00026+1(PC),A0
100: BSR L00022
101: MOVEQ #K00001,D7
102: MOVEQ #K0000E,D6
103: L00030:LEA L00027(PC),A0
104: MOVEA.L A5,A6
105: MOVE.W #K0001D,D5
106: MOVE.W #K00028,D0
107: L0002A:MOVE.B #K00029,(A0)+
108: DBRA D0,L0002A
109: L0002F:MOVE.W D7,D0
110: ANDI.B #K0002B,D0
111: MOVE.B K00001(A3,D0.W),D0
112: MOVE.B D0,(A0)+
113: MOVE.B #K0002C,(A0)+
114: MOVE.B #K00029,(A0)+
115: MOVE.W D7,D0
116: LSL.W #K00004,D0
117: MOVEA.L (A6)+,A1
118: MOVE.W K00001(A1,D0.W),D0
119: MOVEQ #K0002D,D2
120: L0002E:ROL.W #K0000E,D0
121: MOVE.B D0,D1
122: ANDI.B #K0002B,D1
123: EXT.W D1
124: MOVE.B K00001(A3,D1.W),D1
125: MOVE.B D1,(A0)+
126: DBRA D2,L0002E
127: MOVE.B #K00029,(A0)+
128: MOVE.B #K00029,(A0)+
129: DBRA D5,L0002F
130: MOVE.B #K00001,(A0)
131: LEA L00027(PC),A0
132: BSR L00022
133: LEA L00021+1(PC),A0
134: BSR L00022
135: ADDI.W #K00004,D7
136: DBRA D6,L00030
137: ADDI.W #K00004,L0001E
138: RTS
139: L00011:MOVE.L A5,D1
140: MOVE.W D3,D0
141: TRAP #K0000D
142: RTS
143: L00022:MOVE.L A0,-(A7)
144: MOVE.W #K00031,-(A7)
145: TRAP #K00004
146: ADDQ.L #6,A7
147: RTS
148: L00008:DC.W K00028
149: DC.W $24F4
150: DC.W K00028
151: DC.W $24FE
152: DC.W K00028
153: DC.W $2508
154: DC.W K00028
155: DC.W $2512
156: DC.W K00028
157: DC.W $251C
158: DC.W K00028
159: DC.W $2526
160: L00023:DC.W K00028
161: DC.W $2304
162: DC.W K00028
163: DC.W $2329
164: DC.W K00028
165: DC.W $2363
166: DC.W K00028
167: DC.W $239E
168: DC.W K00028
169: DC.W $23D8
170: DC.W $D0A ;">CR<>LF<"
171: DC.W $5445 ;"TE"
172: DC.W $5354 ;"ST"
173: DC.W $2050 ;" P"
174: DC.W $4F49 ;"OI"
175: DC.W $4E54 ;"NT"
176: DC.W $2030 ;" 0"
177: DC.W $3A20 ;": "
178: DC.W $4265 ;"Be"
179: DC.W $666F ;"fo"
180: DC.W $7265 ;"re"
181: DC.W $2061 ;" a"
182: DC.W $7070 ;"pp"
183: DC.W $6C5F ;"l_"
184: DC.W $696E ;"in"
185: DC.W $6974 ;"it"
186: DC.W $D0A ;">CR<>LF<"
187: DC.W $D0A ;">CR<>LF<"
188: DC.W $D ;">0<>CR<"
189: DC.W $A54 ;">LF<T"
190: DC.W $4553 ;"ES"
191: DC.W $5420 ;"T "
192: DC.W $504F ;"PO"
193: DC.W $494E ;"IN"
194: DC.W $5420 ;"T "
195: DC.W $313A ;"1:"
196: DC.W $2041 ;" A"
197: DC.W $6674 ;"ft"
198: DC.W $6572 ;"er"
199: DC.W $2061 ;" a"
200: DC.W $7070 ;"pp"
201: DC.W $6C5F ;"l_"
202: DC.W $696E ;"in"
203: DC.W $6974 ;"it"
204: DC.W $2C20 ;", "
205: DC.W $6265 ;"be"
206: DC.W $666F ;"fo"
207: DC.W $7265 ;"re"
208: DC.W $206D ;" m"
209: DC.W $656E ;"en"
210: DC.W $755F ;"u_"
211: DC.W $7265 ;"re"
212: DC.W $6769 ;"gi"
213: DC.W $7374 ;"st"
214: DC.W $6572 ;"er"
215: DC.W $D0A ;">CR<>LF<"
216: DC.W $D0A ;">CR<>LF<"
217: DC.W $D ;">0<>CR<"
218: DC.W $A54 ;">LF<T"
219: DC.W $4553 ;"ES"
220: DC.W $5420 ;"T "
221: DC.W $504F ;"PO"
222: DC.W $494E ;"IN"
223: DC.W $5420 ;"T "
224: DC.W $323A ;"2:"
225: DC.W $2041 ;" A"
226: DC.W $6674 ;"ft"
227: DC.W $6572 ;"er"
228: DC.W $206D ;" m"
229: DC.W $656E ;"en"
230: DC.W $755F ;"u_"
231: DC.W $7265 ;"re"
232: DC.W $6769 ;"gi"
233: DC.W $7374 ;"st"
234: DC.W $6572 ;"er"
235: DC.W $2C20 ;", "
236: DC.W $6265 ;"be"
237: DC.W $666F ;"fo"
238: DC.W $7265 ;"re"
239: DC.W $2065 ;" e"
240: DC.W $766E ;"vn"
241: DC.W $745F ;"t_"
242: DC.W $6D65 ;"me"
243: DC.W $7361 ;"sa"
244: DC.W $670D ;"g>CR<"
245: DC.W $A0D ;">LF<>CR<"
246: DC.W $A00 ;">LF<>0<"
247: DC.W $D0A ;">CR<>LF<"
248: DC.W $5445 ;"TE"
249: DC.W $5354 ;"ST"
250: DC.W $2050 ;" P"
251: DC.W $4F49 ;"OI"
252: DC.W $4E54 ;"NT"
253: DC.W $2033 ;" 3"
254: DC.W $3A20 ;": "
255: DC.W $496E ;"In"
256: DC.W $206D ;" m"
257: DC.W $6573 ;"es"
258: DC.W $7361 ;"sa"
259: DC.W $6765 ;"ge"
260: DC.W $2068 ;" h"
261: DC.W $616E ;"an"
262: DC.W $646C ;"dl"
263: DC.W $6572 ;"er"
264: DC.W $2C20 ;", "
265: DC.W $6265 ;"be"
266: DC.W $666F ;"fo"
267: DC.W $7265 ;"re"
268: DC.W $2065 ;" e"
269: DC.W $766E ;"vn"
270: DC.W $745F ;"t_"
271: DC.W $6D65 ;"me"
272: DC.W $7361 ;"sa"
273: DC.W $670D ;"g>CR<"
274: DC.W $A0D ;">LF<>CR<"
275: DC.W $A00 ;">LF<>0<"
276: DC.W $D0A ;">CR<>LF<"
277: DC.W $5445 ;"TE"
278: DC.W $5354 ;"ST"
279: DC.W $2050 ;" P"
280: DC.W $4F49 ;"OI"
281: DC.W $4E54 ;"NT"
282: DC.W $2034 ;" 4"
283: DC.W $3A20 ;": "
284: DC.W $496E ;"In"
285: DC.W $206D ;" m"
286: DC.W $6573 ;"es"
287: DC.W $7361 ;"sa"
288: DC.W $6765 ;"ge"
289: DC.W $2068 ;" h"
290: DC.W $616E ;"an"
291: DC.W $646C ;"dl"
292: DC.W $6572 ;"er"
293: DC.W $2073 ;" s"
294: DC.W $6563 ;"ec"
295: DC.W $6F6E ;"on"
296: DC.W $6420 ;"d "
297: DC.W $7469 ;"ti"
298: DC.W $6D65 ;"me"
299: DC.W $D0A ;">CR<>LF<"
300: DC.W $D0A ;">CR<>LF<"
301: L0000A:DC.W $30 ;">0<0"
302: DC.W $3132 ;"12"
303: DC.W $3334 ;"34"
304: DC.W $3536 ;"56"
305: DC.W $3738 ;"78"
306: DC.W $3941 ;"9A"
307: DC.W $4243 ;"BC"
308: DC.W $4445 ;"DE"
309: L00021:DC.W $460D ;"F>CR<"
310: DC.W $A00 ;">LF<>0<"
311: DC.W $2020 ;" "
312: DC.W $2020 ;" "
313: DC.W $2020 ;" "
314: DC.W $2020 ;" "
315: DC.W $2020 ;" "
316: DC.W $2020 ;" "
317: DC.W $2020 ;" "
318: DC.W $2020 ;" "
319: DC.W $2020 ;" "
320: DC.W $2020 ;" "
321: DC.W $2020 ;" "
322: DC.W $2020 ;" "
323: DC.W $2020 ;" "
324: DC.W $2020 ;" "
325: DC.W $2020 ;" "
326: DC.W $2020 ;" "
327: DC.W $4145 ;"AE"
328: DC.W $5320 ;"S "
329: DC.W $4152 ;"AR"
330: DC.W $5241 ;"RA"
331: DC.W $5953 ;"YS"
332: DC.W $D0A ;">CR<>LF<"
333: L00025:DC.W $43 ;">0<C"
334: DC.W $4F4E ;"ON"
335: DC.W $5452 ;"TR"
336: DC.W $4F4C ;"OL"
337: DC.W $2020 ;" "
338: DC.W $474C ;"GL"
339: DC.W $4F42 ;"OB"
340: DC.W $414C ;"AL"
341: DC.W $2020 ;" "
342: DC.W $2049 ;" I"
343: DC.W $4E54 ;"NT"
344: DC.W $5F49 ;"_I"
345: DC.W $4E20 ;"N "
346: DC.W $2020 ;" "
347: DC.W $494E ;"IN"
348: DC.W $545F ;"T_"
349: DC.W $4F55 ;"OU"
350: DC.W $5420 ;"T "
351: DC.W $2041 ;" A"
352: DC.W $4444 ;"DD"
353: DC.W $525F ;"R_"
354: DC.W $494E ;"IN"
355: DC.W $2020 ;" "
356: DC.W $4144 ;"AD"
357: DC.W $4452 ;"DR"
358: DC.W $5F4F ;"_O"
359: DC.W $5554 ;"UT"
360: DC.W $D0A ;">CR<>LF<"
361: L00026:DC.W $2D ;">0<-"
362: DC.W $2D2D ;"--"
363: DC.W $2D2D ;"--"
364: DC.W $2D2D ;"--"
365: DC.W $2020 ;" "
366: DC.W $2D2D ;"--"
367: DC.W $2D2D ;"--"
368: DC.W $2D2D ;"--"
369: DC.W $2D20 ;"- "
370: DC.W $202D ;" -"
371: DC.W $2D2D ;"--"
372: DC.W $2D2D ;"--"
373: DC.W $2D2D ;"--"
374: DC.W $2020 ;" "
375: DC.W $2D2D ;"--"
376: DC.W $2D2D ;"--"
377: DC.W $2D2D ;"--"
378: DC.W $2D20 ;"- "
379: DC.W $202D ;" -"
380: DC.W $2D2D ;"--"
381: DC.W $2D2D ;"--"
382: DC.W $2D2D ;"--"
383: DC.W $2020 ;" "
384: DC.W $2D2D ;"--"
385: DC.W $2D2D ;"--"
386: DC.W $2D2D ;"--"
387: DC.W $2D2D ;"--"
388: DC.W $D0A ;">CR<>LF<"
389: L00024:DC.W K00029 ;">0< "
390: DC.W $2020 ;" "
391: DC.W $2020 ;" "
392: DC.W $2020 ;" "
393: DC.W $2020 ;" "
394: DC.W $2020 ;" "
395: DC.W $2000 ;" >0<"
396: DC.W $2020 ;" "
397: L00015:DC.W K00029 ;">0< "
398: DC.W $2041 ;" A"
399: DC.W $6363 ;"cc"
400: DC.W $6573 ;"es"
401: DC.W $736F ;"so"
402: DC.W $7279 ;"ry"
403: DC.W $2041 ;" A"
404: DC.W $7272 ;"rr"
405: DC.W $6179 ;"ay"
406: DC.W $7320 ;"s "
407: L00002:DC.W $45 ;">0<E"
408: DC.W $3A5C ;":\"
409: DC.W $5052 ;"PR"
410: DC.W $475F ;"G_"
411: DC.W $385C ;"8\"
412: DC.W $5052 ;"PR"
413: DC.W $475F ;"G_"
414: DC.W $3841 ;"8A"
415: DC.W $522E ;"R."
416: DC.W $4441 ;"DA"
417: DC.W $5400 ;"T>0<"
418: L00009:DC.W K00001
419: DC.W K00001
420: DC.W K00001
421: DC.W K00001
422: DC.W K00001
423: L00013:DC.W K00001
424: DC.W K00001
425: DC.W K00001
426: DC.W K00001
427: DC.W K00001
428: L00014:DC.W K00001
429: DC.W K00001
430: DC.W K00001
431: DC.W K00001
432: DC.W K00001
433: L00017:DC.W K00001
434: DC.W K00001
435: DC.W K00001
436: DC.W K00001
437: DC.W K00001
438: L00016:DC.W K00001
439: DC.W K00001
440: DC.W K00001
441: DC.W K00001
442: DC.W K00001
443: DC.W K00001
444: DC.W K00001
445: DC.W K00001
446: DC.W K00001
447: DC.W K00001
448: L00005:DC.W K00001
449: L0001E:DC.W K00001
450: L00019:DC.W K00001
451: DC.W K00001
452: DC.W K00001
453: DC.W K00001
454: DC.W K00001
455: DC.W K00001
456: DC.W K00001
457: DC.W K00001
458: L00018:DC.W K00001
459: L00027:DC.W K00001
460: DC.W K00001
Lines 461 - 1097 omitted to conserve space.
1098: DC.W K00001
1099: L00000:DC.W K00001
1100: DC.W K00001
1101: END
If you have the TEMPUS editor, you should exit AssemPro and
load the disassembly file into one window, then load the
reassembly file into another. Then you can choose the underneath
option to observe both files simultaneously. Alternately, you
can use a word processor such as 1st Word Plus; otherwise, you
will have to work with the files individually, but I intend to
proceed with the discussion as if you are able to view both files
simultaneously. Do not attempt to print either of the files on
your printer yet.
Compressing the Reassembly Listing
The particular example that I am using provides a reassembly
listing that is easily reworked. Other programs do not.
Regardless of the its condition, the reassembly listing is
usually the one that is altered so that it becomes a source
program; however, the disassembly listing provides visual
information that is sometimes obscured in the reassembly listing.
As an example of the difference in information content of the
listings, notice that virtually every number in the reassembly
listing has been replaced by a constant identifier. We must
change every one of those back to the original numbers so that we
can see what it is that the program does. We can do that as we
go along, or we can replace them all at once with the editor's
replace function. Initially, I prefer to make changes
individually until I know it is safe to perform a mass replace.
Notice also that most of the addresses in the reassembly listing
have been converted to labels. There is a list of the constant
identifiers and their values at the beginning of the reassembly
listing, but it is sometimes easier to refer to the disassembly
listing to obtain those values.
As the first instruction in the reassembly listing, you can
see that the address of label L00000 is being loaded into
register A7. That means, of course, that L00000 is the AssemPro
generated label for the stack. If you run down the listing to
L00000, you will see that it is the last label in the program,
and you will see that it is preceded by a long list of DC.W
K00001 pseudo ops. If you now run up to the K00001 declaration
at the top of the listing, you will see that K00001 is the
identifier for the quantity 0.
Now run back down to L00000, then carefully run back up to
the next label, which is L00027. All of the DC.W 0 pseudo ops
between L00027 and L00000 are bss declarations in the original
program. Unfortunately, AssemPro does not differentiate between
data and bss declarations when it generates the reassembly
listing. But that's ok; we can find out where we are by
referring to the disassembly listing and the information in the
basepage. Now, what we don't know is how many of those DC.W 0
declarations belong to L00027 and how many belong to L00000.
That's ok too, because it doesn't matter; in the source program,
the space reserved was only cosmetically separated. The
declarations in the original program would have had to have been
similar to that shown below.
L00027: ds.l xxx
ds.l yyy
L00000: ds.l zzz
where the space reserved by xxx and that reserved by yyy would
have been inseparable anyway.
All that we need is the total space reserved in the original
program. That can be calculated thus: L00027 is at line number
459 in the listing, and there is a DC.W 0 declared there; L00000
is at line number 1099 in the listing, and there is a DC.W 0
declared there also, but we don't count that one--we only want
those declared from L00027 to L00000 (Refer to the model above.
We desire the sum of xxx and yyy.). Subtracting 459 from 1099
yields 640 (that's declared words), which is 320 longwords.
Since we don't know what portion of this declaration to
allocate to each label, and since it doesn't matter anyway, we
can just split the amount between them, and we can delete all of
the DC.W K00001 declarations from L00027 to L00000. And since we
can determine that there are no other references to the label
L00000 within the program simply by searching for that label, we
can change the reference in the first instruction and the label
itself to stack. After the alteration, the declarations would
appear as shown below.
L00027: ds.l 160 ds.l 160
stack: ds.l 1
Notice that I use lower case letters to indicate items which have
been altered. Notice also that I have declared a single longword
at the stack label, as is indicated in the reassembly listing,
even though we know that in the original program ds.l 0 was used.
That can always be changed later if to do so is desirable.
Finally, notice that we have reduced the number of lines in the
listing from 1101 to 462.
If we had no hint about the output of the program, we could
simply return to the top of the listing and begin to decipher
instructions linearly. But we are able to execute the program
and obtain output in a file. Furthermore, we know that the
program is a desk accessory, so we know a great deal about the
types of instructions within the text segment and something about
the declarations in the data segment. With all of this
knowledge, and with the help of the ASCII characters that are
present, we can begin to reconstruct the data segment of the
program. That activity will permit the most rapid reduction in
listing size.
As you run up the listing from L00027, past L0000A, to label
L00023, notice that there are no labels at locations we might
expect them to be if we refer to the original listing in chapter
10. That's because the labels zero, one, two, three and four
were referenced indirectly within the program. Their locations
were stored in pointer array test_header, and the address of
test_header was stored in an address register. Without knowledge
of the original listing, we would discover that as we work
through the conversion. Still, we can work with the data
declarations and insert the labels as we discover their
locations.
Starting at line 170 of the listing and continuing through
line 417, referring to the program's output and to an ASCII table
when necessary, we reconstruct the data section as shown in the
listing in figure 11.6. We can assume that the carriage
return/linefeed declared at line 170 is part of the declaration
at line 171 because there is no null character between the two
lines. At line 188, you can see how the null character would be
declared; there, note the ">0<>CR<" following the semicolon. The
>0< indicates the null character. The $D for the carriage return
follows the null character at that location. The CR, LF and T
mark the beginning of a new declaration.
Figure 11.6. Partially reconstructed data section.
dc.b $D,$A,'TEST POINT 0: Before appl_init',$D,$A,$D,$A,0
dc.b $D,$A,'TEST POINT 1: After appl_init, before menu_register',$D,$A,$D,$A,0
dc.b $D,$A,'TEST POINT 2: After menu_register, before evnt_mesag',$D,$A,$D,$A,0
dc.b $D,$A,'TEST POINT 3: In message handler, before evnt_mesag',$D,$A,$D,$A,0
dc.b $D,$A,'TEST POINT 4: In message handler second time',$D,$A,$D,$A,0
L0000A: dc.b '0123456789ABCDEF'
L00021+1: dc.b $D,$A,0
dc.b ' AES ARRAYS',$D,$A,0
L00025+1:
dc.b 'CONTROL GLOBAL INT_IN INT_OUT ADDR_IN ADDR_OUT',$D,$A,0
L00026+1
dc.b '_______ ______ ______ _______ _______ ________',$D,$A,0
L00024+1:
dc.b ' ',$D,$A,0
dc.b ' ',$D,$A,0
L00015+1:
dc.b ' Accessory Arrays ',0
L00002+1:
dc.b 'E:\PRG_8\PRG_8AR.DAT',0
As we reconstruct the data segment of the program, we use
dc.b pseudo ops to declare strings, not the dc.w pseudo ops. At
line 309, note that the character F, which is part of the
declaration above L00021, has been combined with the declaration
at L00021. This occurred because a null character was not placed
after the hex_table string in the original program (Remember the
assumption made in the paragraph above--it could be wrong.).
This fact would become evident as we work through the reassembly
listing because there are no references to L00021 within the
listing, but L00021+1 is referenced. You can verify this by
searching through the listing for references to L00021. An
explanation is provided in the last paragraph on page 105 of the
AssemPro manual. The Label+1 phenomenon occurs whenever
AssemPro must create a label at an odd address. We can handle
this by changing L00021 to L00021+1 at line 309 and by placing
the F character in the string to which it belongs.
Concerning the hex string declaration, the pseudo op at line
301 is L0000A:DC.W $30 ;">0<0". This declares a null character
followed by a 0. If we take the time to search for references to
L0000A within the listing, we find that there are none. But
L0000A+1 is referenced at line 37. There, the address of the
table is loaded into A3. We can easily infer that an adjustment
is in order. We can change the L0000A+1 to L0000A and declare
the table as it should be.
As it is with L00021, there is no direct reference to
L00025, but L00025+1 is referenced, so we handle line 333 as we
did line 309. L00026 at line 361 is changed to L00026+1. At
line 389, L00024 is changed to L00024+1; and note that the
constant K00029 at that location is just $20, the ASCII code for
a space. Note also that a null character precedes the space. At
line 396 two spaces are declared, following the null on line 395,
and preceding the null on line 396. The space following the null
on line 396 is part of the L00015+1 declaration " Accessory
Arrays ". L00002 at line 407 must be changed to L00002+1, and we
readily observe a file name and directory path at that location.
We can now begin converting statements from the top of the
listing, using the disassembly listing and the list of constant
identifiers to fill in numeric values, and referring to the
appropriate reference books to identify functions. The most
prominent candidates for immediate conversion are the trap
numbers. At each TRAP word, simply exchange the constant
identifier for the constant itself. Then, at each location of a
trap invocation, replace all constant identifiers with constants.
As each function is identified, replace the appropriate label
references within the invocation and at their site if possible.
Above each function invocation, place a suitable label to
describe the function. After doing this for the first two
functions, they would appear as shown in figure 11.7.
Figure 11.7. First two functions of the listing.
create_file:
lea stack(pc), sp
move.w #0, -(sp)
pea filename(pc)
move.w #$3C, -(sp)
trap #1
addq.l #8, sp
move.w d0, file_handle
redirect_output:
move.w file_handle(pc), -(sp)
move.w #1, -(sp)
move.w #$46, -(sp)
trap #1
addq.l #6, sp
As the alterations shown in figure 11.7 are made, L00002+1
must be changed to filename at the label's site, as must L00005
be changed to file_handle. As we are making the file_handle
exchange for L00005, we should notice that the program can be
improved by pushing d0 onto the stack in the redirect_output
function instead of pushing the variable file_handle, as was done
in the original program; but, at this time, we should simply
place a note in the listing to which attention can be directed
later. We want to suppress improvements until we have confirmed
the accuracy of the machine language to assembly language
conversion. Don't forget to declare the ds.w 1 at the
file_handle label site.
As the first two functions are being transformed, the labels
that are replaced there and at the label sites must also be
replaced at all referencing locations. That activity would lead
to the transformation of the two functions that exist at the
L0001F label site. Those two transformed functions are shown in
figure 11.8. Don't forget to alter all references to L0001F when
it is changed to close_file.
Figure 11.8. Two more functions disclosed.
beq.s close_file
BRA.S L0001C
close_file:
move.w file_handle(pc), -(sp)
move.w #$3E, -(sp)
trap #1
addq.l #4, sp
_redirect_output:
move.w #1, -(sp)
move.w file_handle(pc), -(sp)
move.w #$46, -(sp)
trap #1
addq.l #6, sp
The two program statements following the functions shown in
figure 11.8 will lead us to a trap #2 subroutine. The first
statement stores $C8, the AES call number in register D3; the
second statement stores the address of a label in A5. Searching
for all references to A5, eventually leads us to L00011 at which
the trap #2 invocation resides. The very structure of the
subroutine identifies it as the AES call. Thus we are able to
identify L00008 as the label for the aes_pb. And, when all of
the constant identifiers residing just below the BSR L0000B
statement are replaced by the respective constants; and after
observing the BSR L00011 statement just below those replaced
constants, we can be sure that the address of the label being
loaded into register A4 must be that of the array control.
Therefore, each BSR L00011 can be changed to bsr aes, each
reference to L00008 can be changed to a reference to aes_pb and
each reference to L00009 can be changed to a reference to
control. Control can be declared as a five word array thus: ds.w
5.
At this point, we are unable to clearly identify references
to the other five AES structures within the reassembly listing;
but we do know the order in which their addresses must be stored
in the aes_pb structure; therefore, using the disassembly listing
as a guide, we can obtain the address of aes_pb as that which is
being loaded into A5 at line 16, and at that location we can
obtain the addresses of the other structures. At those addresses
we will be able to determine both the amount of space reserved
for each array and the relative positions of those declarations
within the program. We then possess the required information to
declare the structures within the reassembly listing. See figure
11.9, which shows the relevant parts of the disassembly listing.
At address $B22D8, we can see the disassembly listing address of
each of the structures in question.
Figure 11.9. Relevant portions of the disassembly
listing.
0B211A 363C00C8 MOVE.W #$C8,D3
0B211E 4BFA01B8 LEA $B22D8(PC),A5
0B2122 49FA03D0 LEA $B24F4(PC),A4
0B22D6 4E75 RTS
0B22D8 000B DC.W $B
0B22DA 24F4000B MOVE.L $B(A4,D0.W),(A2)+
0B22DE 24FE MOVE.L SR,(A2)+
0B22E0 000B DC.W $B
0B22E2 2508 MOVE.L A0,-(A2)
0B22E4 000B DC.W $B
0B22E6 2512 MOVE.L (A2),-(A2)
0B22E8 000B DC.W $B
0B22EA 251C MOVE.L (A4)+,-(A2)
0B22EC 000B DC.W $B
0B22EE 2526 MOVE.L -(A6),-(A2)
0B22F0 000B DC.W $B
0B22F2 2304 MOVE.L D4,-(A1)
0B22F4 000B DC.W $B
0B22F6 2329000B MOVE.L $B(A1),-(A1)
0B22FA 2363000B MOVE.L -(A3),$B(A1)
0B22FE 239E000B MOVE.L (A6)+,$B(A1,D0.W)
0B2302 23D80D0A5445 MOVE.L (A0)+,$A5445
Section omitted as unnecessary.
0B24F4 00000000 ORI.B #0,D0
0B24F8 00000000 ORI.B #0,D0
0B24FC 00000000 ORI.B #0,D0
0B2500 00000000 ORI.B #0,D0
0B2504 00000000 ORI.B #0,D0
0B2508 00000000 ORI.B #0,D0
0B250C 00000000 ORI.B #0,D0
0B2510 00000000 ORI.B #0,D0
0B2514 00000000 ORI.B #0,D0
0B2518 00000000 ORI.B #0,D0
0B251C 00000000 ORI.B #0,D0
0B2520 00000000 ORI.B #0,D0
0B2524 00000000 ORI.B #0,D0
0B2528 00000000 ORI.B #0,D0
0B252C 00000000 ORI.B #0,D0
0B2530 00000000 ORI.B #0,D0
0B2534 00000000 ORI.B #0,D0
0B2538 00000000 ORI.B #0,D0
0B253C 00000000 ORI.B #0,D0
0B2540 00000000 ORI.B #0,D0
0B2544 00000000 ORI.B #0,D0
0B2548 00000000 ORI.B #0,D0
Using the information in figure 11.9 we easily confirm that
L00013 marks the declaration of the array global; and that
L00014, L00017 and L00016 mark the declarations for int_in,
int_out and addr_in. Notice that no label for addr_out appears
in the reassembly listing. That's because the other structures
were directly referenced within the program, but addr_out was
not. As the labels for the referenced structures are altered,
don't forget to change the label identifiers in the instructions
which reference them. From figure 11.1, the image of a portion
of the program's basepage, we can obtain the information needed
to mark the data and bss seqments of the program. But that
information is also pretty obvious from the layout of the
reassembly and disassembly listings. Don't forget that the align
statement is needed after those dc.b declarations. With the
other AES structures identified, we are able to seek out the
other AES function invocations, and with a knowledge of the input
requirements for those functions and their returns, we are able
to identify the location of the menu text string, the message
array and the variable menu_id.
From the top of the listing again, the BSR L0000B
instruction sends us to the statement which loads L00021+1 into
A0. The BSR L00022 statement just below that sends us to a trap
#1 invocation. Replacing the constant identifier there, K00031,
with 9 readily identifies the function as GEMDOS c_conws, the
print line function, and thereby, we realize that the contents of
A0 must be the address of a string. We have, of course, already
noted that the string declared at L00021+1 is a carriage
return/linefeed combination; we can now choose to replace
references to L00021+1 as references to the label newline, and
references to L00022 as references to print_line.
The five instructions below the branch to the print_line
subroutine accomplish the following:
1. An address is loaded into A0.
2. A value is stored in D0; then the contents of D0 are
multiplied by 4.
3. D0 is used as an index register in an address register
indirect with index instruction to load a new address
into A0.
4. The print_line subroutine is invoked to print a string.
We conclude that L00023, the label identifying the address
which is loaded into A0 in item 1, must be that of a pointer
array that contains the addresses of the strings that are to be
processed by the five instructions. Referring to the disassembly
listing, where we see that the address loaded into A0 is $B22F0,
then by observing the data stored at that address, we confirm
that such is the case.
Figure 11.10 contains a section of the disassembly listing
that is relevant to the identification of each address stored in
the pointer array, and just enough of the beginning of each
string. You could easily confirm that the strings stored at
those locations match those of the reassembly listing simply by
converting each of the ASCII codes in the disassembly listing to
characters.
Figure 11.10. The section of the disassembly listing
containing the addresses referenced in the pointer
array at $B22F0.
0B2302 23D80D0A5445 MOVE.L (A0)+,$A5445
0B2308 5354 SUBQ.W #1,(A4)
0B2328 000D DC.W $D
0B232A 0A544553 EORI.W #$4553,(A4)
0B2362 000D DC.W $D
0B2364 0A544553 EORI.W #$4553,(A4)
0B2392 745F MOVEQ #$5F,D2
0B2394 6D65 BLT.S $B23FB
0B23D6 0A000D0A EORI.B #$A,D0
0B23DA 5445 ADDQ.W #2,D5
We need not be concerned with the actual names used for the
labels of the strings; we need only realize that we must place
labels at their declarations and store those labels in the
pointer array in place of the addresses that are present in the
reassembly listing. Let us chose to use "string_zero" for the
first, to match the "TEST POINT 0" reference within the string
itself, and continue with the rest of them through "string_four".
Remember that the pseudo op for the pointer array declaration at
L00023 must be dc.l, for two reasons. The first is that 32-bit
addresses are being stored in the array; the second is that the
run time addresses would not be stored if a ds pseudo op were
used.
Still within the same subroutine, after the five
instructions which lead us to the pointer array, there are a
series of loads into A0 followed by branches to the print_line
subroutine. The labels referenced in that area are those that we
left with the "+1" excess baggage. We can now alter those labels
and the references to them to L00024, L00025 and L00026. In
addition we can replace the two constant identifiers, K00001 and
K0000E by the actual values that are stored in registers D7 and
D6. At the conclusion of that activity, we will have arrived at
label L00030.
At this point, it would be advantageous to exchange each of
the constant identifiers remaining in the subroutine for the
actual constants. Simultaneously, we can convert upper case
statements which require no alterations to lower case as an
indication that we need not be concerned about the format of
those statements. Figure 11.11 shows the reassembly listing at
its current stage of reconstruction.
Figure 11.11. The partially reconstructed reassembly
listing.
K00001=0 K00003=$3C K00004=1 K00006=$46 K00007=$C8 K0000C=$A
K0000D=2 K0000E=4 K0000F=6 K00010=8 K00012=$23 K0001A=$17
K0001B=$28 K0001D=5 K00020=$3E K00028=$B K00029=$20 K0002B=$F
K0002C=$3A K0002D=3 K00031=9
create_file:
lea stack(pc), sp
move.w #0, -(sp)
pea filename(pc)
move.w #$3C, -(sp)
trap #1
addq.l #8, sp
move.w d0, file_handle
redirect_output:
move.w file_handle(pc), -(sp) ; CAN USE D0 FOR IMPROVEMENT.
move.w #1, -(sp)
move.w #$46, -(sp)
trap #1
addq.l #6, sp
move.w #$C8, d3
lea aes_pb(pc), a5
lea control(pc)
lea L0000A(PC), a3
BSR L0000B
initialize_application:
move.w #$A, (a4)
move.w #0, 2(a4)
move.w #1, 4(a4)
move.w #0, 6(a4)
move.w #0, 8(a4)
bsr aes
BSR L0000B
menu_register:
move.w #$23, (a4)
move.w #1, 2(a4)
move.w #1, 4(a4)
move.w #1, 6(a4)
move.w #0, 8(a4)
lea global(pc), a0
move.w 4(a0), int_in
move.l #menu_text, addr_in
bsr aes
move.w int_out(pc), menu_id
BSR L0000B
move.l #message, addr_in
evnt_mesag:
move.w #$17, (a4)
move.w #0, 2(a4)
move.w #1, 4(a4)
move.w #1, 6(a4)
move.w #0, 8(a4)
bsr aes
lea message(pc), a0
cmpi.w #$28, (a0)
bne.s evnt_mesag
move.w 8(a0), d0
cmp.w menu_id(pc), d0
bne.s evnt_mesag
cmpi.w #5, L0001E
beq.s evnt_mesag
BSR L0000B
cmpi.w #5, L0001E
beq.s close_file
bra.s evnt_mesag
close_file:
move.w file_handle(pc), -(sp)
move.w #$3E, -(sp)
trap #1
addq.l #4, sp
_redirect_output:
move.w #1, -(sp)
move.w file_handle(pc), -(sp)
move.w #$46, -(sp)
trap #1
addq.l #6, sp
bra.s evnt_mesag
L0000B:
lea newline(pc), a0
bsr print_line
LEA L00023(PC),A0
MOVE.W L0001E(PC),D0
lsl.w #2, d0 ; Multiply by 4.
movea.l 0(a0,d0.w), a0
bsr print_line
lea L00024(pc), a0
bsr print_line
lea L00025(pc), a0
bsr print_line
lea L00024(pc), a0
bsr print_line
lea L00026(pc), a0
bsr print_line
moveq #0, d7
moveq #4, d6
L00030:
lea L00027(pc), a0
movea.l a5, a6
move.w #5, d5
move.w #11, d0
L0002A:
move.b #$20, (a0)+ ; $20 = ASCII for space.
dbra d0, L0002A
L0002F:
move.w d7, d0
andi.b #$F, d0
move.b 0(a3,d0.w), d0
move.b d0, (a0)+
move.b #$3A, (a0)+ ; $3A = ASCII for colon.
move.b #$20, (a0)+ ; $20 = ASCII for space.
move.b d7, d0
lsl.w #1, d0
movea.l (a6)+, a1
move.w 0(a1,d0.w), d0
moveq #3, d2
L0002E:
rol.w #4, d0
move.b d0, d1
andi.b #$F, d1
ext.w d1
move.b 0(a3,d1.w), d1
move.b d1, (a0)+
dbra d2, L0002E
move.b #$20, (a0)+ ; $20 = ASCII for space.
move.b #$20, (a0)+
dbra d5, L0002F
move.b #0, (a0)
lea L00027(pc), a0
bsr print_line
lea newline(pc), a0
bsr print_line
addi.w #1, d7
dbra d6, L00030
addi.w #1, L0001E
rts
aes:
move.l a5, d1
move.w d3, d0
trap #2
rts
print_line:
move.l a0, -(sp)
move.w #9, -(sp)
trap #1
addq.l #6, sp
rts
data
aes_pb: dc.l control,global,int_in,int_out,addr_in,addr_out
L00023:
dc.l string_zero,string_one,string_two,string_three,string_four
string_zero:
dc.b $D,$A,'TEST POINT 0: Before appl_init',$D,$A,$D,$A,0
string_one:
dc.b $D,$A,'TEST POINT 1: After appl_init, before menu_register',$D,$A,$D,$A,0
string_two:
dc.b $D,$A,'TEST POINT 2: After menu_register, before evnt_mesag',$D,$A,$D,$A,0
string_three:
dc.b $D,$A,'TEST POINT 3: In message handler, before evnt_mesag',$D,$A,$D,$A,0
string_four:
dc.b $D,$A,'TEST POINT 4: In message handler second time',$D,$A,$D,$A,0
L0000A: dc.b '0123456789ABCDEF'
newline: dc.b $D,$A,0
dc.b ' AES ARRAYS',$D,$A,0 ; Label is unknown.
L00025:
dc.b 'CONTROL GLOBAL INT_IN INT_OUT ADDR_IN ADDR_OUT',$D,$A,0
L00026:
dc.b '_______ ______ ______ _______ _______ ________',$D,$A,0
L00024:
dc.b ' ',$D,$A,0
dc.b ' ',$D,$A,0 ; Label is unknown.
menu_text:
dc.b ' Accessory Arrays ',0
filename:
dc.b 'E:\PRG_8\PRG_8AR.DAT',0
bss
align
control: ds.w 5
global: ds.w 5
int_in: ds.w 5
int_out: ds.w 5
addr_in: ds.w 5
addr_out: ds.w 5
file_handle: ds.w 1
L0001E:DC.W K00001
message: ds.w 8
menu_id: ds.w 1
L00027: ds.l 160
ds.l 160
stack: ds.l 1
end
I would now like to draw your attention to two particular
declarations within the listing. I have marked them with the
comment Label is unknown. The first declaration is just below
the newline label; the second is just above L00015+1. In the
original program, the label at the first declaration was
"aes_header"; the label at the second was "spaces". There is no
reference to these labels in the reassembly listing because they
were never referenced in the original program. You can confirm
the omission of the first just by looking at the program's
output. The header does not appear. I had intended that it
should, therefore, its omission is an error. The second
declaration should have been removed from the original program
because I replaced the function that was to be performed with the
"spaces" declaration with in-line code.
You can be sure that you will observe similar errors and
superfluous statements in other programs that you reconstruct.
In fact, you can be sure that you will sometimes see superflous
statements that have been deliberately inserted in a program to
hinder a reconstruction of the source program. Other ploys
include self-modifying code and hardware devices which provide
signals for the program. Examples will be investigated later.
Concluding the Reconstruction
We can choose to continue with the source program
reconstruction by returning to the top of the program and resolve
any further label references, or we can immerse ourselves in the
subroutine which seems to accomplish most of the work in the
program. One activity that can be immediately identified is that
which follows the evnt_mesag function invocation. The
comparisons performed there; comparing #$28 to message[0], and
menu_id to message[4]; clearly marks this as the message handler
algorithm; therefore, we can designate it as such. Then, let us
turn our attention to the program's major subroutine.
The third instruction of the subroutine loads the address of
the pointer array declared at L00023 into A0; the fourth moves
the contents of the variable declared at L0001E into D0; the
fifth multiplies the value of that variable by 4; and in the
sixth instruction, D0 is used as an index register to load a new
address into A0. We already know that the pointer array contains
the addresses of the strings declared just below the pointer
array declaration.
The series of instructions which setup D0 and A0 so that a
selection from that group of strings depends on the value stored
at L0001E tend to indicate that the value at that location is
dynamic. Indeed, if we search the reassembly listing for other
references to L0001E, we see that the value stored there is
compared to the value 5 in two instructions, and it is
incremented as the last instruction in the subroutine. Since the
value stored at L0001E is used in an index register that
determines the choice from a group of strings which identify
themselves as TEST POINTS, we need little imagination to rename
the variable test_number or some other name that is indicative of
its function, and then to properly perform a bss declaration.
Remember to alter all references to L0001E. Figure 11.12 shows
the reconstructed, but untested, listing.
Figure 11.12. Reconstructed source listing.
; PRG_8AR.ASM
; MAJOR NOTE:
; THIS PROGRAM MAY NOT FUNCTION CORRECTLY IF TURBO ST IS INSTALLED.
; This program has been reconstructed from PRG_8AR.ACC.
create_file:
lea stack(pc), sp
move.w #0, -(sp)
pea filename(pc)
move.w #$3C, -(sp)
trap #1
addq.l #8, sp
move.w d0, file_handle
redirect_output:
move.w file_handle(pc), -(sp) ; CAN USE D0 FOR IMPROVEMENT.
move.w #1, -(sp)
move.w #$46, -(sp)
trap #1
addq.l #6, sp
move.w #$C8, d3
lea aes_pb(pc), a5
lea control(pc), a4
lea L0000A(PC), a3
BSR L0000B
initialize_application:
move.w #$A, (a4)
move.w #0, 2(a4)
move.w #1, 4(a4)
move.w #0, 6(a4)
move.w #0, 8(a4)
bsr aes
BSR L0000B
menu_register:
move.w #$23, (a4)
move.w #1, 2(a4)
move.w #1, 4(a4)
move.w #1, 6(a4)
move.w #0, 8(a4)
lea global(pc), a0
move.w 4(a0), int_in
move.l #menu_text, addr_in
bsr aes
move.w int_out(pc), menu_id
BSR L0000B
move.l #message, addr_in
evnt_mesag:
move.w #$17, (a4)
move.w #0, 2(a4)
move.w #1, 4(a4)
move.w #1, 6(a4)
move.w #0, 8(a4)
bsr aes
message_handler:
lea message(pc), a0
cmpi.w #$28, (a0)
bne.s evnt_mesag
move.w 8(a0), d0
cmp.w menu_id(pc), d0
bne.s evnt_mesag
cmpi.w #5, test_number
beq.s evnt_mesag
BSR L0000B
cmpi.w #5, test_number
beq.s close_file
bra.s evnt_mesag
close_file:
move.w file_handle(pc), -(sp)
move.w #$3E, -(sp)
trap #1
addq.l #4, sp
_redirect_output:
move.w #1, -(sp)
move.w file_handle(pc), -(sp)
move.w #$46, -(sp)
trap #1
addq.l #6, sp
bra.s evnt_mesag
L0000B:
lea newline(pc), a0
bsr print_line
LEA L00023(PC),A0
move.w test_number(pc), d0
lsl.w #2, d0 ; Multiply by 4.
movea.l 0(a0,d0.w), a0
bsr print_line
lea L00024(pc), a0
bsr print_line
lea L00025(pc), a0
bsr print_line
lea L00024(pc), a0
bsr print_line
lea L00026(pc), a0
bsr print_line
moveq #0, d7
moveq #4, d6
L00030:
lea L00027(pc), a0
movea.l a5, a6
move.w #5, d5
move.w #11, d0
L0002A:
move.b #$20, (a0)+ ; $20 = ASCII for space.
dbra d0, L0002A
L0002F:
move.w d7, d0
andi.b #$F, d0
move.b 0(a3,d0.w), d0
move.b d0, (a0)+
move.b #$3A, (a0)+ ; $3A = ASCII for colon.
move.b #$20, (a0)+ ; $20 = ASCII for space.
move.b d7, d0
lsl.w #1, d0
movea.l (a6)+, a1
move.w 0(a1,d0.w), d0
moveq #3, d2
L0002E:
rol.w #4, d0
move.b d0, d1
andi.b #$F, d1
ext.w d1
move.b 0(a3,d1.w), d1
move.b d1, (a0)+
dbra d2, L0002E
move.b #$20, (a0)+ ; $20 = ASCII for space.
move.b #$20, (a0)+
dbra d5, L0002F
move.b #0, (a0)
lea L00027(pc), a0
bsr print_line
lea newline(pc), a0
bsr print_line
addi.w #1, d7
dbra d6, L00030
addi.w #1, test_number
rts
aes:
move.l a5, d1
move.w d3, d0
trap #2
rts
print_line:
move.l a0, -(sp)
move.w #9, -(sp)
trap #1
addq.l #6, sp
rts
data
aes_pb: dc.l control,global,int_in,int_out,addr_in,addr_out
L00023:
dc.l string_zero,string_one,string_two,string_three,string_four
string_zero:
dc.b $D,$A,'TEST POINT 0: Before appl_init',$D,$A,$D,$A,0
string_one:
dc.b $D,$A,'TEST POINT 1: After appl_init, before menu_register',$D,$A,$D,$A,0
string_two:
dc.b $D,$A,'TEST POINT 2: After menu_register, before evnt_mesag',$D,$A,$D,$A,0
string_three:
dc.b $D,$A,'TEST POINT 3: In message handler, before evnt_mesag',$D,$A,$D,$A,0
string_four:
dc.b $D,$A,'TEST POINT 4: In message handler second time',$D,$A,$D,$A,0
L0000A: dc.b '0123456789ABCDEF'
newline: dc.b $D,$A,0
dc.b ' AES ARRAYS',$D,$A,0
L00025:
dc.b 'CONTROL GLOBAL INT_IN INT_OUT ADDR_IN ADDR_OUT',$D,$A,0
L00026:
dc.b '_______ ______ ______ _______ _______ ________',$D,$A,0
L00024:
dc.b ' ',0
dc.b ' ',$D,$A,0
menu_text:
dc.b ' Accessory Arrays ',0
filename:
dc.b 'E:\PRG_8\PRG_8AR.DAT',0
bss
align
control: ds.w 5
global: ds.w 5
int_in: ds.w 5
int_out: ds.w 5
addr_in: ds.w 5
addr_out: ds.w 5
file_handle: ds.w 1
test_number: ds.w 1
message: ds.w 8
menu_id: ds.w 1
L00027: ds.l 160
ds.l 160
stack: ds.l 1
end
Actually, I have assembled the program and tested it.
That's why I know that it will not function correctly if my
version of TURBO ST is installed. And there are other problems.
That's why I was forced to write a program to assist with the
corrections that are necessary to make the reconstructed listing
produce object code that is identical to the object code from
which we have generated the source.
