diff --git a/src/tic.c b/src/tic.c
index 4005021..e2baf0f 100644
--- a/src/tic.c
+++ b/src/tic.c
@@ -904,7 +904,7 @@ static void api_textri(tic_mem* memory, s32 x1, s32 y1, s32 x2, s32 y2, s32 x3,
 
 							s32 iu = (s32)u % MapWidth;
 							s32 iv = (s32)v % MapHeight;
-							
+
 							u8 tile = map[(iv>>3) * TIC_MAP_WIDTH + (iu>>3)];
 							const u8 *buffer = &ptr[tile << 5];
 							u8 color = tic_tool_peek4(buffer, (iu & 7) + ((iv & 7) << 3));
@@ -913,8 +913,10 @@ static void api_textri(tic_mem* memory, s32 x1, s32 y1, s32 x2, s32 y2, s32 x3,
 						}
 						else
 						{
-							s32 iu = (s32)(u) & 127;
-							s32 iv = (s32)(v) & 255;
+							enum{SheetWidth = TIC_SPRITESHEET_SIZE, SheetHeight = TIC_SPRITESHEET_SIZE * TIC_SPRITE_BANKS};
+
+							s32 iu = (s32)(u) & (SheetWidth - 1);
+							s32 iv = (s32)(v) & (SheetHeight - 1);
 							const u8 *buffer = &ptr[((iu >> 3) + ((iv >> 3) << 4)) << 5];
 							u8 color = tic_tool_peek4(buffer, (iu & 7) + ((iv & 7) << 3));
 							if (color != chroma)
diff --git a/src/tic.h b/src/tic.h
index 6a59513..a58c726 100644
--- a/src/tic.h
+++ b/src/tic.h
@@ -57,7 +57,8 @@
 
 #define BITS_IN_BYTE 8
 #define TIC_BANK_SPRITES (1 << BITS_IN_BYTE)
-#define TIC_SPRITES (TIC_BANK_SPRITES * 2)
+#define TIC_SPRITE_BANKS 2
+#define TIC_SPRITES (TIC_BANK_SPRITES * TIC_SPRITE_BANKS)
 
 #define TIC_SPRITESHEET_SIZE 128