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cc65/libsrc/tgi/tgi_map_mode.s

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;
; Ullrich von Bassewitz, 31.05.2002
;
; const char* __fastcall__ tgi_map_mode (unsigned char mode);
; /* Map tgi mode codes to driver names */
;
.export _tgi_map_mode
.import _tgi_mode_table
.import return0
.importzp tmp1
;----------------------------------------------------------------------------
; BEWARE: The current implementation of tgi_map_mode does not work with tables
; larger that 255 bytes!
.code
_tgi_map_mode:
sta tmp1 ; Save mode
ldy #$00
@L0: lda _tgi_mode_table,y
beq NotFound ; Branch if mode code zero
cmp tmp1
beq Found
; Skip the name
@L1: iny
lda _tgi_mode_table,y
bne @L1 ; Loop until end marker found
iny ; Skip end marker
bne @L0 ; Branch always
; Mode not found
NotFound:
jmp return0
; Mode found
Found: tya
ldx #>_tgi_mode_table
sec ; Account for the mode byte
adc #<_tgi_mode_table ; Return pointer to file name
rts