git.y1.nz

commit 37821f14ab0b82c031154ffd61e72d144ace6f24
parent 668af23ba29af23f2aebe9736b3a8d8e366c38a2
Author: Toxa <untoxa@mail.ru>
Date:   Mon, 13 Mar 2023 16:37:02 +0300

GB: convert gb_decompress routines to the new calling convention

Diffstat:
M
gbdk-lib/include/gb/gbdecompress.h
8
++++----
M
gbdk-lib/libc/targets/sm83/gb_decompress.s
22
++++++++--------------
M
gbdk-lib/libc/targets/sm83/gb_decompress_tiles.s
28
+++++++++++-----------------

3 files changed, 23 insertions(+), 35 deletions(-)
diff --git a/gbdk-lib/include/gb/gbdecompress.h b/gbdk-lib/include/gb/gbdecompress.h
@@ -23,7 +23,7 @@
 
     @see gb_decompress_bkg_data, gb_decompress_win_data, gb_decompress_sprite_data, rle_decompress
  */
-uint16_t gb_decompress(const uint8_t * sour, uint8_t * dest) OLDCALL PRESERVES_REGS(b, c);
+uint16_t gb_decompress(const uint8_t * sour, uint8_t * dest);
 
 
 /** gb-decompress background tiles into VRAM
@@ -40,7 +40,7 @@ uint16_t gb_decompress(const uint8_t * sour, uint8_t * dest) OLDCALL PRESERVES_R
 
     @see gb_decompress_bkg_data, gb_decompress_win_data, gb_decompress_sprite_data
 */
-void gb_decompress_bkg_data(uint8_t first_tile, const uint8_t * sour) OLDCALL PRESERVES_REGS(b, c);
+void gb_decompress_bkg_data(uint8_t first_tile, const uint8_t * sour);
 
 
 /** gb-decompress window tiles into VRAM
@@ -60,7 +60,7 @@ void gb_decompress_bkg_data(uint8_t first_tile, const uint8_t * sour) OLDCALL PR
 
     @see gb_decompress, gb_decompress_bkg_data, gb_decompress_sprite_data
  */
-void gb_decompress_win_data(uint8_t first_tile, const uint8_t * sour) OLDCALL PRESERVES_REGS(b, c);
+void gb_decompress_win_data(uint8_t first_tile, const uint8_t * sour);
 
 
 /** gb-decompress sprite tiles into VRAM
@@ -77,6 +77,6 @@ void gb_decompress_win_data(uint8_t first_tile, const uint8_t * sour) OLDCALL PR
 
     @see gb_decompress, gb_decompress_bkg_data, gb_decompress_win_data
  */
-void gb_decompress_sprite_data(uint8_t first_tile, const uint8_t * sour) OLDCALL PRESERVES_REGS(b, c);
+void gb_decompress_sprite_data(uint8_t first_tile, const uint8_t * sour);
 
 #endif
 
diff --git a/gbdk-lib/libc/targets/sm83/gb_decompress.s b/gbdk-lib/libc/targets/sm83/gb_decompress.s
@@ -9,18 +9,13 @@
         .area _CODE
 
 _gb_decompress::
-        lda     hl,5(SP)
-        ld      a,(hl-)
-        ld      d,a
-        ld      a,(hl-)
-        ld      e,a
-        ld      a,(hl-)
-        ld      l,(hl)
-        ld      h,a
+        ld      h,d
+        ld      l,e
+        ld      d,b
+        ld      e,c
 
 ; hl = source; de = dest
 gb_decompress::
-        push    bc
         push    de
 1$:
         ld      a,(hl+) ; load command
@@ -88,7 +83,7 @@ gb_decompress::
         and     #63
         inc     a
         ld      b,a
-8$:                    
+8$:
         ld      a,(hl+)
         ld      (de),a
         inc     de
@@ -99,10 +94,9 @@ gb_decompress::
         pop     hl
         ld      a, e
         sub     l
-        ld      e, a
+        ld      c, a
         ld      a, d
         sbc     h
-        ld      d, a
-        pop     bc
-        
+        ld      b, a
+
         ret
diff --git a/gbdk-lib/libc/targets/sm83/gb_decompress_tiles.s b/gbdk-lib/libc/targets/sm83/gb_decompress_tiles.s
@@ -25,35 +25,30 @@ loc:
 
 _gb_decompress_bkg_data::
 _gb_decompress_win_data::
-        ld      d, #0x90
-        ldh     a, (.LCDC)
-        and     #LCDCF_BG8000
-        jr      z, .load_params
+        ld      b, #0x90
+        ld      hl, #.LCDC
+        bit     LCDCF_B_BG8000, (hl)
+        jr      nz, .load_params
 _gb_decompress_sprite_data::
-        ld      d, #0x80
+        ld      b, #0x80
 
 .load_params:
-        ldhl    sp, #2
-        ld      a, (hl+)
-        
+        ld      h, d
+        ld      l, e
+
         ; Compute dest ptr
         swap    a       ; *16 (size of a tile)
         ld      e, a
         and     #0x0F   ; Get high bits
-        add     d       ; Add base offset of target tile "block"
+        add     b       ; Add base offset of target tile "block"
         ld      d, a
         ld      a, e
         and     #0xF0   ; Get low bits only
         ld      e, a
         WRAP_VRAM d
 
-        ld      a, (hl+)
-        ld      h, (hl)
-        ld      l, a
-
 ; hl = source; de = dest
 gb_decompress_vram::
-        push    bc
         push    de
 1$:
         ld      a,(hl+) ; load command
@@ -78,7 +73,7 @@ gb_decompress_vram::
         dec     c
         jr      nz,2$
         jr      1$      ; next command
-        
+
 3$:                     ; RLE word
         and     #63
         inc     a
@@ -98,7 +93,7 @@ gb_decompress_vram::
         WRAP_VRAM d
         dec     c
         jr      nz,4$
-        inc     hl      
+        inc     hl
         jr      1$      ; next command
 
 5$:
@@ -161,5 +156,4 @@ gb_decompress_vram::
         jp      1$      ; next command
 9$:
         pop     de
-        pop     bc
         ret

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