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cc65/libsrc/plus4/ksetnam.s

60 lines
1.3 KiB
ArmAsm

;
; Ullrich von Bassewitz, 22.11.2002
;
; SETNAM replacement function
;
.export SETNAM
.include "plus4.inc"
; This function is special in that the name must reside in low memory,
; otherwise it is not accessible by the ROM code.
.segment "LOWCODE" ; Must go into low memory
.proc SETNAM
; Store the length of the name into the zero page
sta FNAM_LEN
; Check if we have to copy the name to low memory
cmp #$00 ; Length zero?
beq @L3 ; Yes: Copying not needed
cpy #$00 ; Is the name in low memory?
bpl @L3 ; Yes: Copying not needed
; Store the length and the pointer to the name
stx TMPPTR
sty TMPPTR+1 ; Store pointer to name in TMPPTR
; Copy the given name into FNBUF.
ldy #$00
@L2: lda (TMPPTR),y
sta FNBUF,y
iny
cpy FNAM_LEN
bne @L2
; Load the new parameters for the low memory buffer
ldx #<FNBUF
ldy #>FNBUF
; Instead of banking in the ROM, store the values directly into the zeropage
@L3: stx FNAM
sty FNAM+1
; Return to caller
rts
.endproc