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New entry points for bzero and _bzero

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git-svn-id: svn://svn.cc65.org/cc65/trunk@1277 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2002-05-18 21:18:45 +00:00
parent 4cb4751164
commit 009df2d6b5
1 changed files with 36 additions and 15 deletions
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51
libsrc/common/memset.s
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@ -1,27 +1,50 @@
;
; void* memset (void* ptr, int c, size_t n);
; void* _bzero (void* ptr, size_t n);
; void bzero (void* ptr, size_t n);
;
; Ullrich von Bassewitz, 29.05.1998
;
; NOTE: bzero will return it's first argument as memset does. It is no problem
; to declare the return value as void, since it may be ignored. _bzero
; (note the leading underscore) is declared with the proper return type,
; because the compiler will replace memset by _bzero if the fill value
; is zero, and the optimizer looks at the return type to see if the value
; in a/x is of any use.
;
.export _memset
.export _memset, _bzero, __bzero
.import popax
.importzp ptr1, ptr2, tmp1, tmp2, tmp3
.importzp sp, ptr1, ptr2, ptr3, tmp1
_bzero:
__bzero:
sta ptr3
stx ptr3+1 ; Save n
lda #0
sta tmp1 ; fill with zeros
beq common
_memset:
sta tmp1 ; Save n
stx tmp2
sta ptr3 ; Save n
stx ptr3+1
jsr popax ; Get c
sta tmp3 ; Save c
jsr popax ; Get ptr
sta tmp1 ; Save c
; Common stuff for memset and bzero from here
common:
ldy #1
lda (sp),y
tax
dey
lda (sp),y ; Get ptr
sta ptr1
stx ptr1+1 ; Save work copy
sta ptr2
stx ptr2+1 ; Save a copy for the function result
lda tmp3
lda tmp1 ; Load fill value
ldy #0
ldx tmp2 ; Get high byte of n
ldx ptr3+1 ; Get high byte of n
beq L2 ; Jump if zero
; Set 256 byte blocks
@ -36,8 +59,8 @@ L1: sta (ptr1),y ; Set one byte
bne L1 ; Repeat if any
; Set the remaining bytes if any
L2: ldx tmp1 ; Get the low byte of n
L2: ldx ptr3 ; Get the low byte of n
beq L9 ; Low byte is zero
L3: sta (ptr1),y ; Set one byte
@ -45,8 +68,6 @@ L3: sta (ptr1),y ; Set one byte
dex ; Done?
bne L3
L9: lda ptr2 ; Load function result
ldx ptr2+1
rts
L9: jmp popax ; Pop ptr and return as result