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cc65/libsrc/cbm/toascii.s
uz 1518a4813c The X register must be zero on return.
git-svn-id: svn://svn.cc65.org/cc65/trunk@4426 b7a2c559-68d2-44c3-8de9-860c34a00d81
2009-11-02 16:24:26 +00:00

43 lines
656 B
ArmAsm

;
; Ullrich von Bassewitz, 2009-11-02
;
; unsigned char __fastcall__ toascii (unsigned char c);
; /* Convert a target specific character to ascii */
;
.export _toascii
.macpack generic
.proc _toascii
; X must be zero on return
ldx #0
; Check for code between 65 and 90
cmp #$41
blt @L1
cmp #$5B
bge @L1
; Code between 65 and 90
ora #$20
rts
; Check for code between 193 and 219
@L1: cmp #$C1
blt @L9
cmp #$DC
bge @L9
; Code between 193 and 219
and #$7F
@L9: rts
.endproc