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cc65/libsrc/common/vfscanf.s
cuz 35b7d549f4 Replace vfscanf by an assembler version
git-svn-id: svn://svn.cc65.org/cc65/trunk@3305 b7a2c559-68d2-44c3-8de9-860c34a00d81
2004-11-27 14:56:54 +00:00

71 lines
1.9 KiB
ArmAsm

;
; int __fastcall__ vfscanf (FILE* f, const char* format, va_list ap);
;
; Ullrich von Bassewitz, 2004-11-27
;
.export _vfscanf
.import _fgetc, _ungetc
.include "zeropage.inc"
.include "_scanf.inc"
; ----------------------------------------------------------------------------
; Static scanfdata structure for the _vfscanf routine
;
.data
d: .addr _fgetc ; GET
.addr _ungetc ; UNGET
.addr 0 ; data
; ----------------------------------------------------------------------------
; int __fastcall__ vfscanf (FILE* f, const char* format, va_list ap)
; /* Standard C function */
; {
; struct scanfdata d;
;
; /* Initialize the data struct. We do only need the given file as user data,
; * since the get and ungetc are crafted so they match the standard fgetc
; * and ungetc functions.
; */
; d.get = (getfunc) fgetc,
; d.unget = (ungetfunc) ungetc,
; d.data = f;
;
; /* Call the internal function and return the result */
; return _scanf (&d, format, ap);
; }
;
; Since _scanf has the same parameter stack as vfscanf, with f replaced by &d,
; we will do exactly that. _scanf will then clean up the stack, so we can jump
; directly there, no need to return.
; Beware: Since ap is a fastcall parameter, we must not destroy a/x.
;
.code
_vfscanf:
pha ; Save low byte of ap
; Swap f against &d on the stack, placing f into d.data
ldy #2 ; Offset of f on the stack
lda (sp),y
sta d + SCANFDATA::DATA
lda #<d
sta (sp),y
iny ; High byte
lda (sp),y
sta d + SCANFDATA::DATA + 1
lda #>d
sta (sp),y
; Restore the low byte of ap and jump to the _scanf function
pla
jmp __scanf