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PsL Monthly 1993 December
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PSL Monthly Shareware CD-ROM (December 1993).iso
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prgmming
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dos
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c
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stdlib1.exe
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SPRINTF.ASM
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Assembly Source File
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1990-07-09
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16KB
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819 lines
stdlib segment para public 'slcode'
assume cs:stdlib
extrn sl_ISize:far, sl_ULSize:far
extrn sl_LSize:far, sl_USize:far
extrn sl_itoa:far, sl_free:far
extrn sl_wtoa:far, sl_ltoa:far
extrn sl_ultoa:far, sl_htoa:far
extrn sl_utoa:far
extrn sl_malloc:far, sl_realloc:far
;
;
;
; Sprintf- Like the "C" routine by the same name. Calling sequence:
;
; call sprintf
; db "format string",0
; dd item1, item2, ..., itemn
;
; Just like the PRINTF routine except it performs an in-memory format
; operation rather than printing the data to the current output device.
; Returns a pointer to the formatted string in ES:DI.
; See the PRINTF routine for more details about this guy.
;
;
cr equ 0dh
ff equ 0ch
lf equ 0ah
tab equ 09h
bs equ 08h
;
RtnAdrs equ 2[bp]
;
;
;
aindex dw ?
aptr dd ?
;
;
; sp_BufSize is a public variable so the user can adjust the size.
;
public sp_BufSize
sp_BufSize dw 2048
;
;
public sl_sprintf
sl_sprintf proc far
push bp
mov bp, sp
pushf
push ax cx
;
; Request some memory from the system. If there isn't enough available,
; try half as much and repeat. If there is no memory available, return
; with the carry set.
;
mov cx, sp_BufSize
TryAgain: call sl_malloc
jnc DoSPRINTF
shr cx, 1
cmp cx, 128 ;Need at least 128 bytes.
jae TryAgain
pop cx ax
popf
pop bp
stc
ret
;
; The following code simulates a far call to sbprintf. We can't make the
; call because we need to skip the MOV BP, SP instruction which appears
; at the beginning of the code.
;
DoSPRINTF: push cs ;Push fake return address
mov ax, offset RA
push ax
push bp ;Push stuff on stack
pushf
push ax bx cx dx di si es ds
jmp sl_sbprintf2
;
; Return back to this point from sbprintf.
;
RA: push di
mov cx, 1
mov al, ch
FindLength: cmp al, es:[di]
jz AtEnd
inc cx
inc di
jmp FindLength
;
AtEnd: pop di
call sl_realloc
pop cx ax
popf
pop bp
clc
ret
sl_sprintf endp
;
;
;
;
; SBPRINTF- Like sprintf except it doesn't allocate storage for the
; formatted string. Instead, you must pass it the address of a suitable
; buffer in es:di.
;
;
public sl_sbprintf
sl_sbprintf proc far
push bp
mov bp, sp
pushf
push ax bx cx dx di si es ds
;
; Save ptr to buffer area.
;
sl_sbprintf2: mov word ptr cs:aptr, di
mov word ptr cs:aptr+2, es
mov cs:aindex, 0
;
; Get pointers to the return address (format string).
;
cld
les di, RtnAdrs
lds si, RtnAdrs
;
; Okay, search for the end of the format string. After these instructions,
; di points just beyond the zero byte at the end of the format string. This,
; of course, points at the first address beyond the format string.
;
mov al, 0
mov cx, 65535
repne scasb
;
PrintItems: lodsb ;Get char si points at.
cmp al, 0 ;EOS?
jz PrintfDone
cmp al, "%" ;Start of a format string?
jz FmtItem
cmp al, "\" ;Escape character?
jnz PrintIt
call GetEscChar
PrintIt: call PutIt
jmp PrintItems
;
FmtItem: call GetFmtItem ;Process the format item here.
jmp PrintItems
;
PrintfDone: mov RtnAdrs, di ;Put out new return address.
pop ds
pop es
pop si
pop di
pop dx
pop cx
pop bx
pop ax
pop bp
popf
clc
ret
sl_sbprintf endp
;
; GetEscChar- Handles items immediately following the escape character "\".
;
; Special escape characters (upper/lower case is acceptable):
;
; n Newline (cr/lf)
; t tab
; b backspace
; r return
; l line feed
; f formfeed
; \ \
; % &
; 0xhh Char with hex character code hh. Must have exactly
; two hexadecimal digits.
;
GetEscChar proc near
lodsb ;Get next character
cmp al, 'n'
je RtnNL
cmp al, 'N'
je RtnNL
cmp al, 't'
je RtnTab
cmp al, 'T'
je RtnTab
cmp al, 'b'
je RtnBS
cmp al, 'B'
je RtnBS
cmp al, 'r'
je RtnRtn
cmp al, 'R'
je RtnRtn
cmp al, 'l'
je RtnLF
cmp al, 'L'
je RtnLF
cmp al, 'f'
je RtnFF
cmp al, 'F'
je RtnFF
;
; Check for the presence of a 0xhh value here:
;
cmp al, '0'
jne RtnChar
cmp byte ptr [si], 'x'
je GetHex
cmp byte ptr [si], 'X'
jne RtnChar
;
; Okay, process the hex value here. Note that exactly two hex digits must
; follow the 0x.
;
GetHex: inc si ;Point at first hex digit.
lodsb ;Get first hex digit.
and al, 05fh ;l.c. -> u.c.
cmp al, 'A'
jb GotIt
sub al, '7'
GotIt: shl al, 1 ;Put into H.O. nibble.
shl al, 1
shl al, 1
shl al, 1
mov ah, al ;Save for later
lodsb ;Get next char.
and al, 05fh
cmp al, 'A'
jb GotIt2
sub al, '7'
GotIt2: and al, 0fh
or al, ah
ret ;Return hex constant.
;
; RtnNL (return Newline) cheats. It needs to return two characters.
; Since GetEscChar only returns a single character, this code goes ahead
; and calls putc to output the CR and the returns the LF.
;
RtnNL: mov al, cr
call PutIt
mov al, lf
ret
;
RtnTab: mov al, tab
ret
;
RtnBS: mov al, bs
ret
;
RtnRtn: mov al, cr
ret
;
RtnLF: mov al, lf
ret
;
RtnFF: mov al, ff
RtnChar: ret
;
GetEscChar endp
;
;
;
GetFmtItem proc near
lodsb ;Get char beyond "%"
;
mov cx, 1 ;Default field width is 1.
mov dl, 0 ;Default is right justified
mov dh, ' ' ;Default fill char is space.
mov ah, ' ' ;Assume straight ptr, not handle.
;
; See if the user wants the value left justified:
;
cmp al, '-'
jne NotLeftJust
inc dl ;Set to right justified
lodsb ;Get next character.
;
; See if the user wants to change the padding character.
;
NotLeftJust: cmp al, '\'
jne NoPadChange
lodsb ;Get Padding Character.
mov dh, al ;Save padding character.
lodsb ;Get next character
;
; See if the user wants a different field width:
;
NoPadChange: cmp al, '0'
jb NoFldWidth
cmp al, '9'
ja NoFldWidth
call GetDecVal
;
; See if the user wants to specify a handle rather than a straight pointer
;
NoFldWidth: cmp al, '^'
jne ChkFmtChars
mov ah, al
lodsb ;Skip "^" character
;
; Okay, process the format characters down here.
;
ChkFmtChars: and al, 05fh ;l.c. -> U.C.
cmp al, 'D'
je PrintDec
cmp al, 'I'
je PrintDec
cmp al, 'C'
je PrintChar
;
cmp al, 'X'
jne TryH
jmp PrintHexWord
;
TryH: cmp al, 'H'
jne TryU
jmp PrintHexByte
;
TryU: cmp al, 'U'
jne TryString
jmp PrintUDec
;
TryString: cmp al, 'S'
jne TryLong
jmp PrintString
;
TryLong: cmp al, 'L'
jne Default
;
; If we've got the "L" modifier, this is a long value to print, get the
; data type character as the next value:
;
lodsb
and al, 05fh ;l.c. -> U.C.
cmp al, 'D'
je JmpDec
cmp al, 'I'
jne TryLU
JmpDec: jmp LongDec
;
TryLU: cmp al, 'U'
jne TryX
jmp LongU
;
TryX: cmp al, 'X'
jne Default
jmp LongX
;
;
;
; If none of the above, simply return without printing anything.
;
Default: ret
;
;
;
;
;
; Print a signed decimal value here.
;
PrintDec: call GetPtr ;Get next pointer into ES:BX
mov ax, es:[bx] ;Get value to print.
call sl_ISize ;Get the size of this guy.
sub cx, ax ;Compute padding
mov ax, es:[bx] ;Retrieve value to print.
js NoPadDec ;Is CX negative?
cmp dl, 0 ;Right justified?
jne LeftJustDec
call PrintPad ;Print padding characters
call PutIti ;Print the integer
ret ;We're done!
;
; Print left justified value here.
;
LeftJustDec: call PutIti
call PrintPad
ret
;
; Print non-justified value here:
;
NoPadDec: call PutIti
ret
;
;
;
; Print a character variable here.
;
PrintChar: call GetPtr ;Get next pointer into ES:BX
mov al, es:[bx] ;Retrieve value to print.
dec cx
js NoPadChar ;Is CX negative?
cmp dl, 0 ;Right justified?
jne LeftJustChar
call PrintPad ;Print padding characters
call PutIt ;Print the character
ret ;We're done!
;
; Print left justified value here.
;
LeftJustChar: