git.y1.nz

commit 159abbcdbaa25a09a6c876b0b5f80fb3cc9bfa68
parent 5887b74086f7b96644685d025ed8699a4dcfcb87
Author: Toxa <untoxa@mail.ru>
Date:   Wed, 10 Feb 2021 15:16:14 +0300

get_bkg_xy_addr()/get_win_xy_addr()

Diffstat:
M
gbdk-lib/examples/gb/scroller/text_scroller.c
37
+++++++++++++++++++------------------
M
gbdk-lib/include/gb/gb.h
8
++++----
M
gbdk-lib/libc/gb/get_addr.s
41
++++++++++++++++++++++++++++++-----------
M
gbdk-lib/libc/gb/set_tile.s
6
+++---

4 files changed, 56 insertions(+), 36 deletions(-)
diff --git a/gbdk-lib/examples/gb/scroller/text_scroller.c b/gbdk-lib/examples/gb/scroller/text_scroller.c
@@ -46,25 +46,26 @@ void main() {
         set_interrupts(VBL_IFLAG | LCD_IFLAG);
     }
 
-	scroller_vram_addr = set_bkg_tile_xy(20, SCROLL_POS, *scroller_next_char - 0x20);
-	
-	base = (UWORD) scroller_vram_addr & 0xffe0;
-	limit = base + 0x20;
-	
+    scroller_vram_addr = get_bkg_xy_addr(20, SCROLL_POS);
+    set_vram_byte(scroller_vram_addr, *scroller_next_char - 0x20);
+    
+    base = (UWORD) scroller_vram_addr & 0xffe0;
+    limit = base + 0x20;
+    
     while (1) {
-		scroller_x++;
-		if ((scroller_x & 0x07) == 0) {
-			// next letter
-			scroller_next_char++;
-			if (*scroller_next_char == 0) scroller_next_char = scroller_text;
-			
-			// next vram position
-			scroller_vram_addr++;
-			if (scroller_vram_addr == (UBYTE *)limit) scroller_vram_addr = (UBYTE *)base;
-			
-			// put next char
-			set_vram_byte(scroller_vram_addr, *scroller_next_char - 0x20);
-		}
+        scroller_x++;
+        if ((scroller_x & 0x07) == 0) {
+            // next letter
+            scroller_next_char++;
+            if (*scroller_next_char == 0) scroller_next_char = scroller_text;
+            
+            // next vram position
+            scroller_vram_addr++;
+            if (scroller_vram_addr == (UBYTE *)limit) scroller_vram_addr = (UBYTE *)base;
+            
+            // put next char
+            set_vram_byte(scroller_vram_addr, *scroller_next_char - 0x20);
+        }
         wait_vbl_done();        
     }
 }
 
diff --git a/gbdk-lib/include/gb/gb.h b/gbdk-lib/include/gb/gb.h
@@ -619,9 +619,9 @@ void set_vram_byte(UBYTE * addr, UINT8 v) __preserves_regs(b, c);
 
 
 /**
- * Get base address of background map
+ * Get address of X,Y tile of background map
  */
-UINT8 * get_bkg_map_addr() __preserves_regs(b, c, h, l);
+UINT8 * get_bkg_xy_addr(UINT8 x, UINT8 y) __preserves_regs(b, c);
 
 
 /** Sets VRAM Tile Pattern data for the Background / Window
@@ -804,9 +804,9 @@ inline void scroll_bkg(INT8 x, INT8 y) {
 
 
 /**
- * Get base address of window map
+ * Get address of X,Y tile of window map
  */
-UINT8 * get_win_map_addr() __preserves_regs(b, c, h, l);
+UINT8 * get_win_xy_addr(UINT8 x, UINT8 y) __preserves_regs(b, c);
 
 /** Sets VRAM Tile Pattern data for the Window / Background
 
diff --git a/gbdk-lib/libc/gb/get_addr.s b/gbdk-lib/libc/gb/get_addr.s
@@ -2,19 +2,38 @@
 
 .area _CODE
 
-_get_win_map_addr::
-        ldh     a,(.LCDC)
-        bit     6,a
-        jr      z,.is98
+_get_win_xy_addr::
+        ldh     a, (.LCDC)
+        bit     6, a
+        jr      z, .is98
         jr      .is9c
 
-_get_bkg_map_addr::
-        ldh     a,(.LCDC)
-        bit     3,a
-        jr      nz,.is9c
+_get_bkg_xy_addr::
+        ldh     a, (.LCDC)
+        bit     3, a
+        jr      nz, .is9c
 .is98:
-        ld      de,#0x9800      ; DE = origin
-        ret
+        ld      d, #0x98        ; DE = origin
+        jr      .calculate_ofs
 .is9c:
-        ld      de,#0x9C00      ; DE = origin
+        ld      d, #0x9C        ; DE = origin
+
+.calculate_ofs:
+        ldhl    sp, #3
+
+        ld      a, (hl-)
+        ld      l, (hl)
+
+        ld      e, d
+        swap    a
+        rlca
+        ld      h, a
+        and     #0x03
+        add     e
+        ld      d, a
+        ld      a, #0xE0
+        and     h
+        add     l
+        ld      e, a            ; dest DE = BASE + 0x20 * Y + X
+
         ret
diff --git a/gbdk-lib/libc/gb/set_tile.s b/gbdk-lib/libc/gb/set_tile.s
@@ -27,10 +27,10 @@ _set_bkg_tile_xy::
         bit     3,a
         jr      nz,.is9c
 .is98:
-        ld      de,#0x9800      ; DE = origin
-	jr      .set_tile_xy
+        ld      d,#0x98         ; DE = origin
+        jr      .set_tile_xy
 .is9c:
-        ld      de,#0x9C00      ; DE = origin
+        ld      d,#0x9C         ; DE = origin
 
 .set_tile_xy:
         push    bc

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