bopti-cg: add p8, p4, and fix alignment issues on r5g6b5

TODO

@@ -10,6 +10,7 @@ Tests to run.
 * topti:     all charsets
 
 Complementary elements on existing code.
+*            make fx9860g projects work out of the box on fxcg50
 * topti:     support unicode fonts
 * gray:      find good values for more models than the Graph 35+E II
 * dma:       maybe relax the 4-byte size constraint for dma_memset()

src/render-cg/bopti-asm.h

@@ -22,6 +22,24 @@ void bopti_r5g6b5(uint16_t const *data, uint16_t *target, int width,
 void bopti_r5g6b5a(uint16_t const *data, uint16_t *target, int width,
 	int height, int in_stride, int out_stride, uint16_t alpha);
 
+/* bopti_p8(): 8-bit palette rendering with alpha
+   @data @target @width @height @in_stride @out_stride
+            As in bopti_r5g6b5().
+   @palette Pointer to image palette (256 colors)
+   @alpha   Palette index for transparency, if >= 256 no alpha is used */
+void bopti_p8(uint8_t const *data, uint16_t *target, int width, int height,
+	int in_stride, int out_stride, uint16_t const *palette, int alpha);
+
+/* bopti_p4(): 4-bit palette rendering with alpha
+   @data @target @width @height @in_stride @out_stride
+            As in bopti_r5g6b5().
+   @palette Pointer to image palette (16 colors)
+   @alpha   Palette index for transparency, if >= 16 no alpha is used
+   @offset  Initial offset within [data], in number of pixels */
+void bopti_p4(uint8_t const *data, uint16_t *target, int width, int height,
+	int in_stride, int out_stride, uint16_t const *palette, int alpha,
+	int offset);
+
 /* bopti_render_clip(): Render with clipping
    Same parameters as dsubimage(), except for flags. */
 void bopti_render_clip(int x, int y, image_t const *img, int left, int top,

src/render-cg/bopti-asm.s

@@ -1,6 +1,8 @@
 
 .global _bopti_r5g6b5
 .global _bopti_r5g6b5a
+.global _bopti_p8
+.global _bopti_p4
 
 # REGISTER ALLOCATION:
 # r0: (tmp)
@@ -36,14 +38,20 @@ _bopti_r5g6b5:
 	add	#-1, r2
 	shll	r2
 
-	# Number of longword operations per row
+	# Input and output strides. Add ending alignment because there is no
-	shlr	r6
+	# corresponding increment in the y-loop.
-
-	# Input and output strides, minus aligment
 	mov.l	@(12, r15), r8
 	mov.l	@(16, r15), r9
-	sub	r3, r8
+	mov	r5, r0
-	sub	r3, r9
+	shll	r6
+	add	r6 ,r0
+	and	#2, r0
+	add	r0, r8
+	add	r0, r9
+
+	# Number of longword operations per row
+	sub	r3, r6
+	shlr2	r6
 
 .r5g6b5_y:
 	# First longword
@@ -136,3 +144,170 @@ _bopti_r5g6b5a:
 
 	rts
 	mov.l	@r15+, r8
+
+# REGISTER ALLOCATION:
+# r0: (tmp)
+# r1: in_stride
+# r2: out_stride
+# r3: x counter
+# ---
+# r4: data
+# r5: target
+# r6: width
+# r7: height
+# ---
+# r8: palette
+# r9: alpha
+# ---
+# @8:  in_stride
+# @12: out_stride
+# @16: palette
+# @20: alpha
+
+.align 4
+
+_bopti_p8:
+	# Load palette and in/out strides
+	mov.l	r8, @-r15
+	mov.l	r9, @-r15
+	mov.l	@(16, r15), r8
+	mov.l	@(8, r15), r1
+	mov.l	@(12, r15), r2
+
+	# Load alpha value
+	mov.l	@(20, r15), r9
+
+.p8_y:
+	mov	r6, r3
+
+.p8_x:
+	mov.b	@r4+, r0
+	extu.b	r0, r0
+	cmp/eq	r0, r9
+	bt	.p8_alpha
+
+	# Pass pixel through palette
+	shll	r0
+	mov.w	@(r0, r8), r0
+	mov.w	r0, @r5
+
+.p8_alpha:
+	dt	r3
+	bf.s	.p8_x
+	add	#2, r5
+
+# -
+
+	add	r1, r4
+	dt	r7
+	bf.s	.p8_y
+	add	r2, r5
+
+# -
+
+	mov.l	@r15+, r9
+	rts
+	mov.l	@r15+, r8
+
+# REGISTER ALLOCATION:
+# r0: (tmp)
+# r1: in_stride (in pixels)
+# r2: out_stride
+# r3: x counter
+# ---
+# r4: data
+# r5: target
+# r6: width
+# r7: height
+# ---
+# r8:  palette
+# r9:  number of pixels of offset into data (r4)
+# r10: alpha
+# ---
+# @12: in_stride
+# @16: out_stride
+# @20: palette
+# @24: alpha
+# @28: initial offset (in pixels)
+
+.align 4
+
+_bopti_p4:
+	mov.l	r8, @-r15
+	mov.l	r9, @-r15
+	mov.l	r10, @-r15
+
+	# Load palette and in/out strides
+	mov.l	@(20, r15), r8
+	mov.l	@(12, r15), r1
+	mov.l	@(16, r15), r2
+
+	# Load initial offset
+	mov.l	@(28, r15), r9
+
+	# Load alpha value
+	mov.l	@(24, r15), r10
+	shll	r10
+
+.p4_y:
+	mov	r6, r3
+
+.p4_x:
+
+	# Load 4 bits from offset r9 (in pixels) within image data (r4). Note
+	# that [shlr] puts bit 0 of the shifted register in T.
+	mov	r9, r0
+	add	#1, r9
+	shlr	r0
+	bt.s	.p4_x_unaligned
+	mov.b	@(r0, r4), r0
+
+.p4_x_aligned:
+
+	# Load 4 bits from the higher half of @r4 and use them to index the
+	# palette. Since the palette has two-byte entries, we need the color
+	# bits to be in position 000xxxx0.
+	shlr2	r0
+	shlr	r0
+	and	#0x1e, r0
+
+	cmp/eq	r0, r10
+	bt	.p4_alpha
+
+	# Pass pixel through palette
+	mov.w	@(r0, r8), r0
+	bra	.p4_alpha
+	mov.w	r0, @r5
+
+.p4_x_unaligned:
+
+	# Load 4 bits from the lower half of @r4 into position 000xxxx0.
+	shll	r0
+	and	#0x1e, r0
+
+	cmp/eq	r0, r10
+	bt	.p4_alpha
+
+	# Pass pixel through palette
+	mov.w	@(r0, r8), r0
+	mov.w	r0, @r5
+
+.p4_alpha:
+
+	dt	r3
+	bf.s	.p4_x
+	add	#2, r5
+
+.p4_y_end:
+
+	add	r1, r9
+	dt	r7
+	bf.s	.p4_y
+	add	r2, r5
+
+# -
+
+	mov.l	@r15+, r10
+	mov.l	@r15+, r9
+	rts
+	mov.l	@r15+, r8

src/render-cg/bopti.c

@@ -25,18 +25,18 @@ void bopti_render(image_t const *img, struct box *box)
 	int out = 2 * (396 - box->w);
 
 	int profile = img->profile;
+	void const *data = img->data;
 
-	if(profile == PX_R5G6B5 || profile == PX_R5G6B5A)
-	{
-		uint16_t const *data = img->data;
 	int w = box->w;
 	int h = box->h;
 
-		data += img->width * box->top + box->left;
+	if(profile == PX_R5G6B5 || profile == PX_R5G6B5A)
-
+	{
 		/* Input stride */
 		int in = 2 * (img->width - w);
 
+		data += 2 * (img->width * box->top + box->left);
+
 		if(profile == PX_R5G6B5)
 			bopti_r5g6b5(data, target, w, h, in, out);
 		else
@@ -44,11 +44,29 @@ void bopti_render(image_t const *img, struct box *box)
 	}
 	else if(profile == PX_P8)
 	{
-		#warning TODO: PX_P8
+		/* Palette has 0x100 entries of 2 bytes each */
+		uint16_t const *palette = data;
+		data += 512;
+
+		int in = img->width - w;
+		data += img->width * box->top + box->left;
+
+		bopti_p8(data, target, w, h, in, out, palette, img->alpha);
 	}
 	else if(profile == PX_P4)
 	{
-		#warning TODO: PX_P4
+		/* Palette has 0x10 entries of 2 bytes each */
+		uint16_t const *palette = data;
+		data += 32;
+
+		/* Due to nibble alignment being a hassle, in this function the
+		   input stride is expressed in pixels. */
+		int in = img->width - w;
+		/* Also we don't move pointers, we just use pixel offsets. */
+		int offset = img->width * box->top + box->left;
+
+		bopti_p4(data, target, w, h, in, out, palette, img->alpha,
+			offset);
 	}
 }