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|
;
; int fastcall vcscanf(const char* format, va_list ap);
;
; 2014-09-10, Greg King
;
.export _vcscanf
.import _cgetc, _cputc
.import popax, pushax, swapstk
.include "../common/_scanf.inc"
; static bool pushed;
; static char back;
;
.bss
pushed: .res 1
back: .res 1
.code
; /* Call-back functions:
; ** (Note: These prototypes must NOT be declared with fastcall! They don't
; ** use (getfunc)'s and (ungetfunc)'s last parameter. Leaving it out of these
; ** prototypes makes more efficient code.)
; */
; ----------------------------------------------------------------------------
; /* Read a character from the console, and return it to an internal function */
; static int get(void) {
; static char C;
;
; if (pushed) {
; pushed = false;
; return (int)back;
; }
; cputc(C = cgetc()); /* echo a typed character */
; return (int)C;
; }
;
get: ldx pushed
beq L1
; Return the old, pushed-back character (instead of getting a new one).
;
dex ; ldx #>$0000
stx pushed
lda back
rts
; Directly read the keyboard.
;
L1: jsr _cgetc
; Echo the character to the screen.
;
pha
jsr _cputc
pla
ldx #>$0000
rts
; ----------------------------------------------------------------------------
; static int cdecl unget(int c) {
; pushed = true;
; return back = c;
; }
;
unget: ldx #1
stx pushed
jsr popax ; get the first argument
sta back
rts
; ----------------------------------------------------------------------------
; int fastcall vcscanf(const char* format, va_list ap) {
; /* Initiate the data structure.
; ** Don't initiate the member that these conio functions don't use.
; */
; static const struct scanfdata d = {
; ( getfunc) get,
; (ungetfunc)unget
; };
;
; /* conio is very interactive. So, don't use any pushed-back character.
; ** Start fresh, each time that this function is called.
; */
; pushed = false;
;
; /* Call the internal function, and return the result. */
; return _scanf(&d, format, ap);
; }
;
; Beware: Because ap is a fastcall parameter, we must not destroy .XA.
;
.proc _vcscanf
; ----------------------------------------------------------------------------
; Static, constant scanfdata structure for the _vcscanf routine.
;
.rodata
d: .addr get ; SCANFDATA::GET
.addr unget ; SCANFDATA::UNGET
; .addr 0 ; SCANFDATA::DATA (not used)
.code
pha ; Save low byte of ap
txa
pha ; Save high byte of ap
ldx #0
stx pushed
; Put &d on the stack in front of the format pointer.
lda #<d
ldx #>d
jsr swapstk ; Swap .XA with top-of-stack
jsr pushax ; Put format pointer back on stack
; Restore ap, and jump to _scanf which will clean up the stack.
pla
tax
pla
jmp __scanf
.endproc
|
