mirror of
https://github.com/cc65/cc65.git
synced 2024-11-04 17:04:58 +00:00
77 lines
1.7 KiB
ArmAsm
77 lines
1.7 KiB
ArmAsm
;
|
|
; int printf (const char* Format, ...);
|
|
;
|
|
; Ullrich von Bassewitz, 1.12.2000
|
|
;
|
|
|
|
.export _printf
|
|
.import _stdout, pushax, addysp, _vfprintf
|
|
.importzp sp, ptr1
|
|
|
|
.macpack generic
|
|
|
|
; ----------------------------------------------------------------------------
|
|
; Data
|
|
|
|
.bss
|
|
|
|
ParamSize: .res 1 ; Number of parameter bytes
|
|
|
|
; ----------------------------------------------------------------------------
|
|
; Code
|
|
|
|
.code
|
|
|
|
|
|
_printf:
|
|
sty ParamSize ; Number of param bytes passed in Y
|
|
|
|
; We are using a (hopefully) clever trick here to reduce code size. On entry,
|
|
; the stack pointer points to the last pushed parameter of the variable
|
|
; parameter list. Adding the number of parameter bytes, would result in a
|
|
; pointer that points *after* the Format parameter.
|
|
; Since we have to push stdout anyway, we will do that here, so
|
|
;
|
|
; * we will save the subtraction of 2 (__fixargs__) later
|
|
; * we will have the address of the Format parameter which needs to
|
|
; be pushed next.
|
|
;
|
|
|
|
lda _stdout
|
|
ldx _stdout+1
|
|
jsr pushax
|
|
|
|
; Now calculate the va_list pointer, which does points to Format
|
|
|
|
lda sp
|
|
ldx sp+1
|
|
add ParamSize
|
|
bcc @L1
|
|
inx
|
|
@L1: sta ptr1
|
|
stx ptr1+1
|
|
|
|
; Push Format
|
|
|
|
ldy #1
|
|
lda (ptr1),y
|
|
tax
|
|
dey
|
|
lda (ptr1),y
|
|
jsr pushax
|
|
|
|
; Load va_list (last and __fastcall__ parameter to vfprintf)
|
|
|
|
lda ptr1
|
|
ldx ptr1+1
|
|
|
|
; Call vfprintf
|
|
|
|
jsr _vfprintf
|
|
|
|
; Cleanup the stack. We will return what we got from vfprintf
|
|
|
|
ldy ParamSize
|
|
jmp addysp
|
|
|