mirror of
https://github.com/cc65/cc65.git
synced 2024-11-18 15:05:14 +00:00
200 lines
4.2 KiB
ArmAsm
200 lines
4.2 KiB
ArmAsm
;
|
|
; int vsnprintf (char* Buf, size_t size, const char* Format, va_list ap);
|
|
;
|
|
; Ullrich von Bassewitz, 2009-09-26
|
|
;
|
|
|
|
.export _vsnprintf, vsnprintf
|
|
.import ldaxysp, popax, incsp2, incsp6
|
|
.import _memcpy, __printf
|
|
.importzp sp, ptr1
|
|
|
|
.macpack generic
|
|
|
|
.data
|
|
|
|
; ----------------------------------------------------------------------------
|
|
;
|
|
; Static data for the _vsnprintf routine
|
|
;
|
|
|
|
outdesc: ; Static outdesc structure
|
|
ccount: .word 0 ; ccount
|
|
func: .word out ; Output function pointer
|
|
bufptr: .word 0 ; ptr
|
|
bufsize:.word 0 ; Buffer size
|
|
|
|
.code
|
|
|
|
; ----------------------------------------------------------------------------
|
|
; vsprintf - formatted output into a buffer
|
|
;
|
|
; int __fastcall__ vsnprintf (char* buf, size_t size, const char* format, va_list ap);
|
|
;
|
|
|
|
_vsnprintf:
|
|
pha ; Save ap
|
|
txa
|
|
pha
|
|
|
|
; Setup the outdesc structure. This is also an additional entry point for
|
|
; vsprintf with ap on stack
|
|
|
|
vsnprintf:
|
|
lda #0
|
|
sta ccount+0
|
|
sta ccount+1 ; Clear ccount
|
|
|
|
; Get the size parameter and replace it by a pointer to outdesc. This is to
|
|
; build a stack frame for the call to _printf.
|
|
; If size is zero, there's nothing to do.
|
|
|
|
ldy #2
|
|
lda (sp),y
|
|
sta ptr1
|
|
|
|
lda #<outdesc
|
|
sta (sp),y
|
|
|
|
iny
|
|
lda (sp),y
|
|
sta ptr1+1
|
|
|
|
ora ptr1
|
|
beq L9
|
|
|
|
lda #>outdesc
|
|
sta (sp),y
|
|
|
|
; Write size-1 to outdesc.uns
|
|
|
|
ldy ptr1+1
|
|
ldx ptr1
|
|
bne L1
|
|
dey
|
|
L1: dex
|
|
stx bufsize+0
|
|
sty bufsize+1
|
|
|
|
; Copy buf to the outdesc.ptr
|
|
|
|
ldy #5
|
|
jsr ldaxysp
|
|
sta bufptr+0
|
|
stx bufptr+1
|
|
|
|
; Restore ap and call _printf
|
|
|
|
pla
|
|
tax
|
|
pla
|
|
jsr __printf
|
|
|
|
; Terminate the string. The last char is either at bufptr+ccount or
|
|
; bufptr+bufsize, whichever is smaller.
|
|
|
|
lda ccount+0
|
|
ldx ccount+1
|
|
cpx bufsize+1
|
|
bne L2
|
|
cmp bufsize+0
|
|
L2: bcc L3
|
|
lda bufsize+0
|
|
ldx bufsize+1
|
|
clc
|
|
L3: adc bufptr+0
|
|
sta ptr1
|
|
txa
|
|
adc bufptr+1
|
|
sta ptr1+1
|
|
|
|
lda #0
|
|
tay
|
|
sta (ptr1),y
|
|
|
|
; Return the number of bytes written and drop buf
|
|
|
|
lda ccount+0
|
|
ldx ccount+1
|
|
jmp incsp2
|
|
|
|
; Bail out if size is zero.
|
|
|
|
L9: pla
|
|
pla ; Discard ap
|
|
lda #0
|
|
tax
|
|
jmp incsp6 ; Drop parameters
|
|
|
|
|
|
; ----------------------------------------------------------------------------
|
|
; Callback routine used for the actual output.
|
|
;
|
|
; static void out (struct outdesc* d, const char* buf, unsigned count)
|
|
; /* Routine used for writing */
|
|
;
|
|
; Since we know, we're called with a pointer to our static outdesc structure,
|
|
; we don't need the pointer passed on the stack.
|
|
|
|
out:
|
|
|
|
; Calculate the space left in the buffer. If no space is left, don't copy
|
|
; any characters
|
|
|
|
lda bufsize+0 ; Low byte of buffer size
|
|
sec
|
|
sbc ccount+0 ; Low byte of bytes already written
|
|
sta ptr1
|
|
lda bufsize+1
|
|
sbc ccount+1
|
|
sta ptr1+1
|
|
bcs @L0 ; Branch if space left
|
|
lda #$00
|
|
sta ptr1
|
|
sta ptr1+1 ; No space left
|
|
|
|
; Replace the pointer to d by a pointer to the write position in the buffer
|
|
; for the call to memcpy that follows.
|
|
|
|
@L0: lda bufptr+0
|
|
clc
|
|
adc ccount+0
|
|
ldy #4
|
|
sta (sp),y
|
|
|
|
lda bufptr+1
|
|
adc ccount+1
|
|
iny
|
|
sta (sp),y
|
|
|
|
; Get Count from stack
|
|
|
|
jsr popax
|
|
|
|
; outdesc.ccount += Count;
|
|
|
|
pha
|
|
clc
|
|
adc ccount+0
|
|
sta ccount+0
|
|
txa
|
|
adc ccount+1
|
|
sta ccount+1
|
|
pla
|
|
|
|
; if (Count > Left) Count = Left;
|
|
|
|
cpx ptr1+1
|
|
bne @L1
|
|
cmp ptr1
|
|
@L1: bcc @L2
|
|
lda ptr1
|
|
ldx ptr1+1
|
|
|
|
; Jump to memcpy, which will cleanup the stack and return to the caller
|
|
|
|
@L2: jmp _memcpy
|
|
|
|
|
|
|