/ The Atari Compendium / The Atari Compendium (Toad Computers) (1994).iso / files / umich / utils / clearmem.arc / READ_ME

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|00000000| 46 72 6f 6d 20 64 69 6c | 6c 6f 6e 40 43 4f 52 59 |From dil|lon@CORY|
|00000010| 2e 42 45 52 4b 45 4c 45 | 59 2e 45 44 55 20 28 4d |.BERKELE|Y.EDU (M|
|00000020| 61 74 74 20 44 69 6c 6c | 6f 6e 29 20 4d 6f 6e 20 |att Dill|on) Mon |
|00000030| 41 75 67 20 31 35 20 32 | 33 3a 34 33 3a 30 30 20 |Aug 15 2|3:43:00 |
|00000040| 31 39 38 38 0a 50 61 74 | 68 3a 20 63 61 65 6e 2e |1988.Pat|h: caen.|
|00000050| 65 6e 67 69 6e 2e 75 6d | 69 63 68 2e 65 64 75 21 |engin.um|ich.edu!|
|00000060| 6d 61 69 6c 72 75 73 21 | 6e 63 61 72 21 61 6d 65 |mailrus!|ncar!ame|
|00000070| 73 21 70 61 73 74 65 75 | 72 21 75 63 62 76 61 78 |s!pasteu|r!ucbvax|
|00000080| 21 43 4f 52 59 2e 42 45 | 52 4b 45 4c 45 59 2e 45 |!CORY.BE|RKELEY.E|
|00000090| 44 55 21 64 69 6c 6c 6f | 6e 0a 46 72 6f 6d 3a 20 |DU!dillo|n.From: |
|000000a0| 64 69 6c 6c 6f 6e 40 43 | 4f 52 59 2e 42 45 52 4b |dillon@C|ORY.BERK|
|000000b0| 45 4c 45 59 2e 45 44 55 | 20 28 4d 61 74 74 20 44 |ELEY.EDU| (Matt D|
|000000c0| 69 6c 6c 6f 6e 29 0a 4e | 65 77 73 67 72 6f 75 70 |illon).N|ewsgroup|
|000000d0| 73 3a 20 63 6f 6d 70 2e | 73 79 73 2e 61 74 61 72 |s: comp.|sys.atar|
|000000e0| 69 2e 73 74 0a 53 75 62 | 6a 65 63 74 3a 20 41 53 |i.st.Sub|ject: AS|
|000000f0| 53 45 4d 42 4c 59 20 4d | 4f 56 45 2f 43 4c 45 41 |SEMBLY M|OVE/CLEA|
|00000100| 52 2f 53 45 54 2f 43 4f | 4d 50 41 52 45 20 52 4f |R/SET/CO|MPARE RO|
|00000110| 55 54 49 4e 45 53 20 28 | 77 61 73 20 43 6c 65 61 |UTINES (|was Clea|
|00000120| 72 69 6e 67 20 6d 65 6d | 6f 72 79 20 63 68 61 69 |ring mem|ory chai|
|00000130| 6e 29 0a 4d 65 73 73 61 | 67 65 2d 49 44 3a 20 3c |n).Messa|ge-ID: <|
|00000140| 38 38 30 38 31 36 30 33 | 34 33 2e 41 41 31 30 32 |88081603|43.AA102|
|00000150| 34 38 40 63 6f 72 79 2e | 42 65 72 6b 65 6c 65 79 |48@cory.|Berkeley|
|00000160| 2e 45 44 55 3e 0a 44 61 | 74 65 3a 20 31 36 20 41 |.EDU>.Da|te: 16 A|
|00000170| 75 67 20 38 38 20 30 33 | 3a 34 33 20 47 4d 54 0a |ug 88 03|:43 GMT.|
|00000180| 53 65 6e 64 65 72 3a 20 | 64 61 65 6d 6f 6e 40 75 |Sender: |daemon@u|
|00000190| 63 62 76 61 78 2e 42 45 | 52 4b 45 4c 45 59 2e 45 |cbvax.BE|RKELEY.E|
|000001a0| 44 55 0a 4c 69 6e 65 73 | 3a 20 32 39 31 0a 0a 3e |DU.Lines|: 291..>|
|000001b0| 49 20 74 68 69 6e 6b 20 | 74 68 69 73 20 70 72 6f |I think |this pro|
|000001c0| 62 6c 65 6d 20 63 6f 75 | 6c 64 20 62 65 20 73 6f |blem cou|ld be so|
|000001d0| 6c 76 65 64 20 71 75 69 | 74 65 20 73 69 6d 70 6c |lved qui|te simpl|
|000001e0| 79 20 62 79 20 75 73 69 | 6e 67 20 6f 6e 65 20 6f |y by usi|ng one o|
|000001f0| 66 20 74 68 65 20 72 65 | 73 65 72 76 65 64 0a 3e |f the re|served.>|
|00000200| 66 69 65 6c 64 73 20 69 | 6e 20 74 68 65 20 47 45 |fields i|n the GE|
|00000210| 4d 44 4f 53 20 65 78 65 | 63 75 74 61 62 6c 65 20 |MDOS exe|cutable |
|00000220| 70 72 6f 67 72 61 6d 20 | 68 65 61 64 65 72 2e 20 |program |header. |
|00000230| 20 4f 6e 65 20 6f 66 20 | 74 68 65 73 65 20 66 69 | One of |these fi|
|00000240| 65 6c 64 73 20 63 6f 75 | 6c 64 20 62 65 0a 3e 75 |elds cou|ld be.>u|
|00000250| 73 65 64 20 66 6f 72 20 | 74 65 6c 6c 69 6e 67 20 |sed for |telling |
|00000260| 74 68 65 20 4f 53 20 74 | 68 61 74 20 69 74 20 64 |the OS t|hat it d|
|00000270| 6f 65 73 20 6e 6f 74 20 | 68 61 76 65 20 74 6f 20 |oes not |have to |
|00000280| 63 6c 65 61 72 20 74 68 | 65 20 54 50 41 20 62 65 |clear th|e TPA be|
|00000290| 66 6f 72 65 65 78 65 63 | 75 74 69 6e 67 0a 09 0a |foreexec|uting...|
|000002a0| 09 48 61 6c 66 20 6f 66 | 20 74 68 69 73 20 63 6f |.Half of| this co|
|000002b0| 6e 76 65 72 73 61 74 69 | 6f 6e 20 69 73 20 73 69 |nversati|on is si|
|000002c0| 6c 6c 79 2e 20 20 53 69 | 6e 63 65 20 77 68 65 6e |lly.  Si|nce when|
|000002d0| 20 69 73 20 63 6c 65 61 | 72 69 6e 67 20 6d 65 6d | is clea|ring mem|
|000002e0| 6f 72 79 0a 73 6c 6f 77 | 3f 20 20 41 20 70 72 6f |ory.slow|?  A pro|
|000002f0| 70 65 72 6c 79 20 77 72 | 69 74 74 65 6e 20 6d 65 |perly wr|itten me|
|00000300| 6d 6f 72 79 2d 73 65 74 | 2f 63 6c 65 61 72 20 66 |mory-set|/clear f|
|00000310| 75 6e 63 74 69 6f 6e 20 | 77 69 6c 6c 20 75 73 65 |unction |will use|
|00000320| 2c 20 73 61 79 2c 20 31 | 32 20 6f 72 20 31 33 0a |, say, 1|2 or 13.|
|00000330| 72 65 67 69 73 74 65 72 | 73 20 66 69 6c 6c 65 64 |register|s filled|
|00000340| 20 77 69 74 68 20 74 68 | 65 20 70 61 74 74 65 72 | with th|e patter|
|00000350| 6e 20 61 6e 64 20 74 68 | 65 6e 20 6c 6f 6f 70 20 |n and th|en loop |
|00000360| 6f 6e 20 6d 6f 76 65 6d | 2e 6c 20 69 6e 73 74 72 |on movem|.l instr|
|00000370| 75 63 74 69 6f 6e 2e 0a | 0a 09 4e 65 65 64 6c 65 |uction..|..Needle|
|00000380| 73 73 20 74 6f 20 73 61 | 79 2c 20 74 68 69 73 20 |ss to sa|y, this |
|00000390| 69 73 20 2a 66 61 73 74 | 2a 2e 20 20 56 65 72 79 |is *fast|*.  Very|
|000003a0| 20 66 61 73 74 2c 20 69 | 6e 20 66 61 63 74 2e 0a | fast, i|n fact..|
|000003b0| 0a 09 41 6e 64 20 62 65 | 66 6f 72 65 20 73 6f 6d |..And be|fore som|
|000003c0| 65 20 6f 66 20 74 68 65 | 20 6c 65 73 73 20 73 6f |e of the| less so|
|000003d0| 70 68 69 73 74 69 63 61 | 74 65 64 20 73 74 61 72 |phistica|ted star|
|000003e0| 74 20 62 6c 61 62 62 65 | 72 69 6e 67 20 61 62 6f |t blabbe|ring abo|
|000003f0| 75 74 0a 73 70 65 63 69 | 61 6c 20 63 61 73 65 73 |ut.speci|al cases|
|00000400| 2c 20 66 6f 6c 6c 6f 77 | 69 6e 67 20 69 73 20 73 |, follow|ing is s|
|00000410| 6f 6d 65 20 2a 47 45 4e | 45 52 41 4c 2a 20 36 38 |ome *GEN|ERAL* 68|
|00000420| 4b 20 63 6f 64 65 20 66 | 6f 72 20 63 6c 65 61 72 |K code f|or clear|
|00000430| 69 6e 67 2c 20 6d 6f 76 | 69 6e 67 2c 0a 61 6e 64 |ing, mov|ing,.and|
|00000440| 20 63 6f 6d 70 61 72 69 | 6e 67 20 6d 65 6d 6f 72 | compari|ng memor|
|00000450| 79 2e 0a 0a 09 41 6c 6c | 20 72 6f 75 74 69 6e 65 |y....All| routine|
|00000460| 73 20 77 6f 72 6b 20 6f | 6e 20 61 72 62 69 74 72 |s work o|n arbitr|
|00000470| 61 72 79 20 62 6f 75 6e | 64 72 69 65 73 2c 20 61 |ary boun|dries, a|
|00000480| 6e 64 20 6f 70 74 69 6d | 69 7a 65 20 61 63 63 6f |nd optim|ize acco|
|00000490| 72 64 69 6e 67 20 74 6f | 0a 74 68 65 20 62 6c 6f |rding to|.the blo|
|000004a0| 63 6b 20 73 69 7a 65 20 | 61 6e 64 20 61 6c 69 67 |ck size |and alig|
|000004b0| 6e 6d 65 6e 74 2c 20 61 | 6c 6c 20 74 68 65 20 77 |nment, a|ll the w|
|000004c0| 61 79 20 74 6f 20 75 73 | 69 6e 67 20 6d 75 6c 74 |ay to us|ing mult|
|000004d0| 69 70 6c 65 2d 72 65 67 | 69 73 74 65 72 20 6d 6f |iple-reg|ister mo|
|000004e0| 76 65 73 0a 74 6f 20 61 | 63 63 6f 6d 70 6c 69 73 |ves.to a|ccomplis|
|000004f0| 68 20 74 68 65 20 67 6f | 61 6c 2e 20 20 62 6d 6f |h the go|al.  bmo|
|00000500| 76 28 29 20 77 69 6c 6c | 20 64 6f 20 65 69 74 68 |v() will| do eith|
|00000510| 65 72 20 61 6e 20 61 73 | 63 65 6e 64 69 6e 67 20 |er an as|cending |
|00000520| 6f 72 20 64 65 63 65 6e | 64 69 6e 67 0a 63 6f 70 |or decen|ding.cop|
|00000530| 79 20 61 63 63 6f 72 64 | 69 6e 67 6c 79 2c 20 61 |y accord|ingly, a|
|00000540| 6c 6c 6f 77 69 6e 67 20 | 66 6f 72 20 6f 76 65 72 |llowing |for over|
|00000550| 6c 61 70 70 65 64 20 6d | 6f 76 65 73 2e 0a 0a 53 |lapped m|oves...S|
|00000560| 50 45 43 49 41 4c 20 4e | 4f 54 45 53 3a 0a 09 2d |PECIAL N|OTES:..-|
|00000570| 41 6c 6c 20 63 61 6c 6c | 73 20 74 61 6b 65 20 33 |All call|s take 3|
|00000580| 32 20 62 69 74 20 71 75 | 61 6e 74 69 74 69 65 73 |2 bit qu|antities|
|00000590| 20 66 6f 72 20 61 6e 79 | 20 70 6f 69 6e 74 65 72 | for any| pointer|
|000005a0| 73 20 6f 72 20 69 6e 74 | 65 67 65 72 73 2e 20 20 |s or int|egers.  |
|000005b0| 4e 6f 74 65 0a 09 2d 65 | 73 70 65 63 69 61 6c 6c |Note..-e|speciall|
|000005c0| 79 20 74 68 61 74 20 74 | 68 65 20 42 53 45 54 28 |y that t|he BSET(|
|000005d0| 29 20 66 75 6e 63 74 69 | 6f 6e 20 74 61 6b 65 73 |) functi|on takes|
|000005e0| 20 61 20 6c 6f 6e 67 20 | 66 6f 72 20 74 68 65 20 | a long |for the |
|000005f0| 66 69 6c 6c 0a 09 20 63 | 68 61 72 61 63 74 65 72 |fill.. c|haracter|
|00000600| 20 65 76 65 6e 20 74 68 | 6f 75 67 68 20 6f 6e 6c | even th|ough onl|
|00000610| 79 20 61 20 63 68 61 72 | 20 69 73 20 75 73 65 64 |y a char| is used|
|00000620| 2e 20 20 53 69 6d 70 6c | 79 20 6d 6f 64 69 66 79 |.  Simpl|y modify|
|00000630| 20 74 68 65 20 63 6f 64 | 65 0a 09 20 74 6f 20 66 | the cod|e.. to f|
|00000640| 69 6c 6c 20 79 6f 75 72 | 20 6e 65 65 64 73 2e 0a |ill your| needs..|
|00000650| 0a 09 2d 54 68 69 73 20 | 61 73 73 65 6d 62 6c 65 |..-This |assemble|
|00000660| 73 20 75 6e 64 65 72 20 | 74 68 65 20 41 7a 74 65 |s under |the Azte|
|00000670| 63 20 61 73 73 65 6d 62 | 6c 65 72 2e 20 20 53 6f |c assemb|ler.  So|
|00000680| 6d 65 20 6d 6f 64 69 66 | 69 63 61 74 69 6f 6e 73 |me modif|ications|
|00000690| 20 6d 61 79 0a 09 20 62 | 65 20 72 65 71 75 69 72 | may.. b|e requir|
|000006a0| 65 64 20 74 6f 20 77 6f | 72 6b 20 6f 6e 20 6f 74 |ed to wo|rk on ot|
|000006b0| 68 65 72 20 61 73 73 65 | 6d 62 6c 65 72 73 2e 20 |her asse|mblers. |
|000006c0| 20 48 6f 77 65 76 65 72 | 2c 20 74 68 65 20 63 6f | However|, the co|
|000006d0| 64 65 20 69 73 0a 09 20 | 43 4f 4d 50 4c 45 54 45 |de is.. |COMPLETE|
|000006e0| 4c 59 20 73 65 6c 66 20 | 63 6f 6e 74 61 69 6e 65 |LY self |containe|
|000006f0| 64 2e 0a 0a 09 2d 43 6f | 64 65 20 69 73 20 73 65 |d....-Co|de is se|
|00000700| 74 20 75 70 20 66 6f 72 | 20 62 65 69 6e 67 20 63 |t up for| being c|
|00000710| 61 6c 6c 65 64 20 66 72 | 6f 6d 20 43 2c 20 77 69 |alled fr|om C, wi|
|00000720| 74 68 20 61 72 67 75 6d | 65 6e 74 73 20 70 75 73 |th argum|ents pus|
|00000730| 68 65 64 20 6f 6e 0a 09 | 20 74 68 65 20 73 74 61 |hed on..| the sta|
|00000740| 63 6b 20 69 6e 20 72 65 | 76 65 72 73 65 20 61 72 |ck in re|verse ar|
|00000750| 67 75 6d 65 6e 74 20 28 | 69 2e 65 2e 20 66 69 72 |gument (|i.e. fir|
|00000760| 73 74 20 61 72 67 20 69 | 73 20 34 28 73 70 29 2c |st arg i|s 4(sp),|
|00000770| 20 73 65 63 6f 6e 64 20 | 69 73 0a 09 20 38 28 73 | second |is.. 8(s|
|00000780| 70 29 2c 20 61 6e 64 20 | 74 68 69 72 64 20 69 73 |p), and |third is|
|00000790| 20 31 32 28 73 70 29 20 | 6f 6e 20 65 6e 74 72 79 | 12(sp) |on entry|
|000007a0| 20 74 6f 20 74 68 65 20 | 63 61 6c 6c 29 0a 0a 09 | to the |call)...|
|000007b0| 2d 44 30 2f 44 31 2f 41 | 30 2f 41 31 20 61 72 65 |-D0/D1/A|0/A1 are|
|000007c0| 20 61 6c 6c 20 61 73 73 | 75 6d 65 64 20 74 6f 20 | all ass|umed to |
|000007d0| 62 65 20 73 63 72 61 74 | 63 68 20 61 6e 64 20 61 |be scrat|ch and a|
|000007e0| 72 65 20 6e 6f 74 20 73 | 61 76 65 64 2e 0a 0a 09 |re not s|aved....|
|000007f0| 09 09 09 09 09 2d 4d 61 | 74 74 0a 0a             |.....-Ma|tt..    |
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