git.y1.nz

commit 2f8d3304c9f733229c04dcbda0936e655a215a2a
parent e0ee5b3e4900ceca69c68f6d6b7c729295f01756
Author: Phidias618 <126189685+Phidias618@users.noreply.github.com>
Date:   Wed,  6 May 2026 23:03:57 +0200

Minor optimizations to the rle_decompress for the sm83
Diffstat:
M
gbdk-lib/libc/targets/sm83/rle_decompress.s
62
+++++++++++++++++++++++++++++---------------------------------

1 file changed, 29 insertions(+), 33 deletions(-)
diff --git a/gbdk-lib/libc/targets/sm83/rle_decompress.s b/gbdk-lib/libc/targets/sm83/rle_decompress.s
@@ -15,10 +15,10 @@ rle_current:
 
 _rle_init::
         ld hl, #rle_cursor
-        ld (hl), e
-        inc hl
-        ld (hl), d
-        inc hl
+        ld a, e
+        ld (hl+), a
+        ld a, d
+        ld (hl+), a
         xor a
         ld (hl+), a
         ld (hl), a
@@ -38,58 +38,55 @@ _rle_decompress::
 
         ld a, (rle_counter)
         or a
+        jr z, 0$
+        
         ld c, a
-        jr z, 1$
-
+        add a
         ld a, (rle_current)
-        bit 7, c
-        jr nz, 10$
-        jr 11$
-1$:
+        jr c, 2$
+        jr 5$
+0$:
         ;; Fetch the run
-        ld c, (hl)
-        inc hl
+        ld a, (hl+)
+        ld c, a
         ;; Negative means a run
-8$:
-        bit 7, c
-        jr z, 2$
+        add a
+        jr nc, 3$
         ;; Expanding a run
         ld a, (hl+)
-3$:
+1$:
         ld (de), a
         inc de
 
         dec b
-        jr z, 6$
-10$:
-        inc c
-        jr nz, 3$
-        jr 1$
+        jr z, 7$
 2$:
-        ;; Zero means end of a block
         inc c
-        dec c
-        jr z, 4$
+        jr nz, 1$
+        jr 0$
+3$:
+        ;; Zero means end of a block
+        jr z, 6$
         ;; Expanding a block
-5$:
+4$:
         ld a, (hl+)
         ld (de), a
         inc de
 
         dec b
-        jr z, 6$
-11$:
+        jr z, 7$
+5$:
         dec c
-        jr nz, 5$
-        jr 1$
-4$:
+        jr nz, 4$
+        jr 0$
+6$:
         ;; save state and exit
         ld hl, #rle_cursor
         xor a
         ld (hl+), a
         ld (hl), a
         ret             ; return 0
-6$:
+7$:
         ;; save state and exit
         ld d, h
         ld e, l
@@ -101,4 +98,4 @@ _rle_decompress::
         ld (hl-), a
         ld (hl), e
         ld a, #1
-        ret             ; return 1
-
+        ret             ; return 1

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