mirror of https://github.com/cc65/cc65.git
130 lines
3.2 KiB
ArmAsm
130 lines
3.2 KiB
ArmAsm
;
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; int fastcall vcscanf(const char* format, va_list ap);
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;
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; 2014-09-10, Greg King
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;
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.export _vcscanf
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.import _cgetc, _cputc
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.import popax, pushax, swapstk
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.include "../common/_scanf.inc"
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; static bool pushed;
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; static char back;
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;
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.bss
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pushed: .res 1
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back: .res 1
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.code
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; /* Call-back functions:
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; ** (Note: These prototypes must NOT be declared with fastcall! They don't
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; ** use (getfunc)'s and (ungetfunc)'s last parameter. Leaving it out of these
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; ** prototypes makes more efficient code.)
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; */
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; ----------------------------------------------------------------------------
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; /* Read a character from the console, and return it to an internal function */
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; static int get(void) {
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; static char C;
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;
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; if (pushed) {
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; pushed = false;
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; return (int)back;
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; }
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; cputc(C = cgetc()); /* echo a typed character */
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; return (int)C;
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; }
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;
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get: ldx pushed
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beq L1
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; Return the old, pushed-back character (instead of getting a new one).
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;
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dex ; ldx #>$0000
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stx pushed
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lda back
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rts
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; Directly read the keyboard.
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;
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L1: jsr _cgetc
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; Echo the character to the screen.
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;
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pha
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jsr _cputc
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pla
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ldx #>$0000
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rts
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; ----------------------------------------------------------------------------
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; static int cdecl unget(int c) {
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; pushed = true;
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; return back = c;
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; }
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;
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unget: ldx #1
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stx pushed
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jsr popax ; get the first argument
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sta back
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rts
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; ----------------------------------------------------------------------------
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; int fastcall vcscanf(const char* format, va_list ap) {
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; /* Initiate the data structure.
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; ** Don't initiate the member that these conio functions don't use.
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; */
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; static const struct scanfdata d = {
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; ( getfunc) get,
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; (ungetfunc)unget
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; };
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;
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; /* conio is very interactive. So, don't use any pushed-back character.
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; ** Start fresh, each time that this function is called.
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; */
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; pushed = false;
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;
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; /* Call the internal function, and return the result. */
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; return _scanf(&d, format, ap);
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; }
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;
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; Beware: Because ap is a fastcall parameter, we must not destroy .XA.
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;
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.proc _vcscanf
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; ----------------------------------------------------------------------------
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; Static, constant scanfdata structure for the _vcscanf routine.
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;
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.rodata
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d: .addr get ; SCANFDATA::GET
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.addr unget ; SCANFDATA::UNGET
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; .addr 0 ; SCANFDATA::DATA (not used)
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.code
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pha ; Save low byte of ap
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txa
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pha ; Save high byte of ap
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ldx #0
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stx pushed
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; Put &d on the stack in front of the format pointer.
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lda #<d
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ldx #>d
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jsr swapstk ; Swap .XA with top-of-stack
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jsr pushax ; Put format pointer back on stack
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; Restore ap, and jump to _scanf which will clean up the stack.
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pla
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tax
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pla
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jmp __scanf
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.endproc
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