git.y1.nz

commit d124b6c3fb4319adc99a744419a8fe1ec2897abb
parent 7fcbf25f39b82e833eacae2f339da44ed1878e37
Author: Toxa <untoxa@mail.ru>
Date:   Sat,  6 Feb 2021 16:58:57 +0300

gb-decompress to VRAM tile wrapping

Diffstat:
M
README.md
2
+-
M
gbdk-lib/include/gb/gbdecompress.h
4
----
M
gbdk-lib/libc/gb/gb_decompress_tiles.s
28
+++++++++++++++-------------

3 files changed, 16 insertions(+), 18 deletions(-)
diff --git a/README.md b/README.md
@@ -45,4 +45,4 @@ Unless you are interested on recompiling the sources for some reason (like fixin
 - Download and install [**sdcc nightlies from 4.0.7 #12016 onwards**](http://sdcc.sourceforge.net/snap.php) (SDCC is no longer part of GDDK so you need to download it (just the binaries) in the platform you need)
 - On Linux **don't use package managers** The latest release available won't work, you need to compile or download one of the nightlies
 - Create **SDCCDIR** environment variable, that points into the folder, where you installed sdcc
-- Open a command prompt or a terminal, go the root directory of the repo and run **make**
+- Open command prompt or a terminal, go to the root directory of the repo and run **make**
diff --git a/gbdk-lib/include/gb/gbdecompress.h b/gbdk-lib/include/gb/gbdecompress.h
@@ -20,8 +20,4 @@ void gb_decompress_win_data(UINT8 first_tile, const unsigned char * sour) __pres
  */
 void gb_decompress_sprite_data(UINT8 first_tile, const unsigned char * sour) __preserves_regs(b, c);
 
-/** gb-decompress data from sour into dest (VRAM-safe)
- */
-void gb_decompress_vram(const unsigned char * sour, unsigned char * dest) __preserves_regs(b, c);
-
 #endif
 
diff --git a/gbdk-lib/libc/gb/gb_decompress_tiles.s b/gbdk-lib/libc/gb/gb_decompress_tiles.s
@@ -3,18 +3,14 @@
 ; GB-Decompress tiledata directly to VRAM
 ; Compatible with GBTD
 
-        .area _CODE
+.macro WRAP_VRAM regH, ?loc
+        bit     3, regH
+        jr      z, loc
+        res     4, regH
+loc:
+.endm
 
-_gb_decompress_vram::
-        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
-        jr      gb_decompress_vram 
+        .area _CODE
 
 _gb_decompress_bkg_data::
 _gb_decompress_win_data::
@@ -38,6 +34,7 @@ _gb_decompress_sprite_data::
         ld      a, e
         and     #0xF0 ; Get low bits only
         ld      e, a
+        WRAP_VRAM d
 
         ld      a, (hl+)
         ld      h, (hl)
@@ -49,7 +46,7 @@ gb_decompress_vram::
 1$:
         ld      a,(hl+) ; load command
         or      a
-        jr      z,9$    ; exit, if last byte
+        jp      z,9$    ; exit, if last byte
         bit     7,a
         jr      nz,5$   ; string functions
         bit     6,a
@@ -63,6 +60,7 @@ gb_decompress_vram::
         ld      a,(hl)
         ld      (de),a
         inc     de
+        WRAP_VRAM d
         dec     b
         jr      nz,2$
         inc     hl
@@ -80,10 +78,12 @@ gb_decompress_vram::
         ld      a,b     ; store word
         ld      (de),a
         inc     de
+        WRAP_VRAM d
         WAIT_STAT
         ld      a,c
         ld      (de),a
         inc     de
+        WRAP_VRAM d
         pop     af
         dec     a
         jr      nz,4$
@@ -107,6 +107,7 @@ gb_decompress_vram::
         ld      a,(hl+)
         ld      (de),a
         inc     de
+        WRAP_VRAM d
         dec     b
         jr      nz,6$
         pop     hl
@@ -122,9 +123,10 @@ gb_decompress_vram::
         ld      a,(hl+)
         ld      (de),a
         inc     de
+        WRAP_VRAM d
         dec     b
         jr      nz,8$
-        jr      1$      ; next command
+        jp      1$      ; next command
 9$:
         pop     bc
         ret

This webpage is intended to be an accessible preview of this repository. To get a fuller picture, clone it and use the git CLI.