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cc65/libsrc/conio/vcprintf.s
2020-12-27 17:54:49 -05:00

150 lines
3.4 KiB
ArmAsm

;
; int __fastcall__ vcprintf (const char* Format, va_list ap);
;
; Ullrich von Bassewitz, 2.12.2000
;
.export _vcprintf
.import pushax, popax, popptr1
.import __printf, _cputc
.importzp sp, ptr1, ptr2, ptr3, tmp1
.macpack generic
.data
; ----------------------------------------------------------------------------
;
; Static data for the _vsprintf routine
;
outdesc: ; Static outdesc structure
.word 0 ; ccount
.word out ; Output function pointer
.word 0 ; ptr
.word 0 ; uns
.code
; ----------------------------------------------------------------------------
; Callback routine used for the actual output.
;
; static void __cdecl__ out (struct outdesc* d, const char* buf, unsigned count)
; /* Routine used for writing */
; {
; /* Fast screen output */
; d->ccount += count;
; while (count) {
; cputc (*buf);
; ++buf;
; --count;
; }
; }
;
; We're using ptr1 and tmp1, since we know that the cputc routine will not use
; them (they're also used in cputs, so they must be safe).
out: jsr popax ; count
sta ptr2
stx ptr2+1
inx
stx outdesc+7
tax
inx
stx outdesc+6
jsr popptr1 ; buf
jsr popax ; d
sta ptr3
stx ptr3+1
; Sum up the total count of characters
ldy #0 ; ccount in struct outdesc
sty tmp1 ; Initialize tmp1 while we have zero available
lda (ptr3),y
add ptr2
sta (ptr3),y
iny
lda (ptr3),y
adc ptr2+1
sta (ptr3),y
; Loop outputting characters
@L1: dec outdesc+6
beq @L4
@L2: ldy tmp1
lda (ptr1),y
iny
bne @L3
inc ptr1+1
@L3: sty tmp1
jsr _cputc
jmp @L1
@L4: dec outdesc+7
bne @L2
rts
; ----------------------------------------------------------------------------
; vcprintf - formatted console i/o
;
; int __fastcall__ vcprintf (const char* format, va_list ap)
; {
; struct outdesc d;
;
; /* Setup descriptor */
; d.fout = out;
;
; /* Do formatting and output */
; _printf (&d, format, ap);
;
; /* Return bytes written */
; return d.ccount;
; }
_vcprintf:
sta ptr1 ; Save ap
stx ptr1+1
; Setup the outdesc structure
lda #0
sta outdesc
sta outdesc+1 ; Clear ccount
; Get the format parameter and push it again
ldy #1
lda (sp),y
tax
dey
lda (sp),y
jsr pushax
; Replace the passed format parameter on the stack by &d - this creates
; exactly the stack frame _printf expects. Parameters will get dropped
; by _printf.
ldy #2 ; Low byte of d
lda #<outdesc
sta (sp),y
iny
lda #>outdesc
sta (sp),y
; Restore ap and call _printf
lda ptr1
ldx ptr1+1
jsr __printf
; Return the number of bytes written.
lda outdesc ; ccount
ldx outdesc+1
rts