Implementing TGI

git-svn-id: svn://svn.cc65.org/cc65/trunk@1311 b7a2c559-68d2-44c3-8de9-860c34a00d81
2002-06-21 12:46:52 +00:00
parent 8c8f0ba06f
commit e50b24d46a
11 changed files with 323 additions and 15 deletions
--- a/libsrc/tgi/tgi_map_mode.s
+++ b/libsrc/tgi/tgi_map_mode.s
@@ -0,0 +1,48 @@
+;
+; 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
+