From: John Tsiombikas <nuclear@member.fsf.org>
Date: Mon, 11 Mar 2024 03:36:18 +0000 (+0200)
Subject: started implementing some GPU abstractions and moved test to C
X-Git-Tag: 0ctri
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=commitdiff_plain;h=a87340cddb40eab47956081c648adc0dfcd6d38d;p=psx_test1

started implementing some GPU abstractions and moved test to C
---

diff --git a/.gitignore b/.gitignore
index 147abfb..ccff81e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,8 @@
 *.psx
 *.map
 *.exe
+*.bin
+*.cue
+license*.dat
+disasm
+*.json
diff --git a/Makefile b/Makefile
index 9cbaf72..dc59471 100644
--- a/Makefile
+++ b/Makefile
@@ -14,7 +14,6 @@ TCPREFIX = mipsel-linux-gnu-
 CC = $(TCPREFIX)gcc
 AS = $(TCPREFIX)as
 LD = $(TCPREFIX)ld
-OBJCOPY = $(TCPREFIX)objcopy
 
 arch = -march=r3000 -msoft-float -mno-abicalls -mno-shared -fno-pic
 
@@ -23,7 +22,7 @@ ASFLAGS = $(arch)
 LDFLAGS = -T psx.ld -print-gc-sections
 
 $(bin): $(elf)
-	$(OBJCOPY) -O binary $< $@
+	$(TCPREFIX)objcopy -O binary $< $@
 
 $(elf): $(obj)
 	$(LD) -o $@ $(obj) -Map link.map $(LDFLAGS)
@@ -36,6 +35,9 @@ $(iso): cd/cd.xml cd/system.cnf $(bin)
 %.s: %.c
 	$(CC) $(CFLAGS) -S -o $@ $<
 
+disasm: $(elf)
+	$(TCPREFIX)objdump -D $< >$@
+
 .PHONY: iso
 iso: $(iso)
 
diff --git a/src/gpu.c b/src/gpu.c
new file mode 100644
index 0000000..bc2f1a4
--- /dev/null
+++ b/src/gpu.c
@@ -0,0 +1,93 @@
+#include "gpu.h"
+#include "psxregs.h"
+
+void gpu_reset(void)
+{
+	REG_GP1 = 0;	/* GPCMD(GP1_RESET) */
+}
+
+void gpu_setmode(int xsz, int ysz, int bpp, int rate)
+{
+	unsigned int x1, y0, y1;
+	unsigned int mode = (ysz >= 480) ? DISP_V480 | DISP_ILACE : 0;
+
+	switch(xsz) {
+	case 320:
+		mode |= DISP_H320;
+		break;
+	case 368:
+		mode |= DISP_H368;
+		break;
+	case 512:
+		mode |= DISP_H512;
+		break;
+	case 640:
+		mode |= DISP_H640;
+		break;
+	default:
+		break;
+	}
+
+	if(bpp >= 24) mode |= DISP_24BPP;
+	if(rate == 50) mode |= DISP_PAL;
+
+	REG_GP1 = GPCMD(GP1_DISPMODE) | mode;
+
+	/* also set display ranges */
+	x1 = 0x260 + 320 * 8;
+	REG_GP1 = GPCMD(GP1_HDISP) | 0x260 | (x1 << 12);
+	if(mode & DISP_PAL) {
+		y0 = 0xa3 - 264 / 2;
+		y1 = 0xa3 + 264 / 2;
+	} else {
+		y0 = 0x88 - 224 / 2;
+		y1 = 0x88 + 224 / 2;
+	}
+	REG_GP1 = GPCMD(GP1_VDISP) | y0 | (y1 << 10);
+}
+
+void gpu_display(int en)
+{
+	REG_GP1 = GPCMD(GP1_DISPEN) | (en ? 0 : 1);
+}
+
+void gpu_cliprect(int x, int y, int w, int h)
+{
+	REG_GP0 = GPCMD(GP0_CLIP_TL) | x | (y << 10);
+	REG_GP0 = GPCMD(GP0_CLIP_BR) | (w - 1) | ((h - 1) << 10);
+}
+
+void gpu_origin(int x, int y)
+{
+	REG_GP0 = GPCMD(GP0_ORIGIN) | x | (y << 11);
+}
+
+/* ---- drawing ---- */
+
+void gpu_fillrect(int x, int y, int w, int h, unsigned int col)
+{
+	REG_GP0 = GPCMD(GP0_FILLRECT) | col;
+	REG_GP0 = x | (y << 16);
+	REG_GP0 = w | (h << 16);
+}
+
+void gpu_draw_flat(int cmd, uint32_t color, struct gpu_vert *data, int vcount)
+{
+	REG_GP0 = GPCMD(cmd) | color;
+	while(vcount-- > 0) {
+		REG_GP0 = *(uint32_t*)data++;
+	}
+}
+
+void gpu_draw_gouraud(int cmd, struct gpu_gvert *data, int vcount)
+{
+	REG_GP0 = GPCMD(cmd) | data->color;
+	REG_GP0 = *(uint32_t*)&data->x;
+	data++;
+
+	while(--vcount > 0) {
+		REG_GP0 = data->color;
+		REG_GP0 = *(uint32_t*)&data->x;
+		data++;
+	}
+}
diff --git a/src/gpu.h b/src/gpu.h
new file mode 100644
index 0000000..81d341f
--- /dev/null
+++ b/src/gpu.h
@@ -0,0 +1,30 @@
+#ifndef GPU_H_
+#define GPU_H_
+
+typedef short int16_t;
+typedef unsigned long uint32_t;
+
+/* flat vertex */
+struct gpu_vert {
+	int16_t x, y;
+};
+
+/* gouraud vertex */
+struct gpu_gvert {
+	uint32_t color;
+	int16_t x, y;
+};
+
+
+void gpu_reset(void);
+void gpu_setmode(int xsz, int ysz, int bpp, int rate);
+void gpu_display(int en);
+void gpu_cliprect(int x, int y, int w, int h);
+void gpu_origin(int x, int y);
+
+void gpu_fillrect(int x, int y, int w, int h, unsigned int col);
+
+void gpu_draw_flat(int cmd, uint32_t color, struct gpu_vert *data, int vcount);
+void gpu_draw_gouraud(int cmd, struct gpu_gvert *data, int vcount);
+
+#endif	/* GPU_H_ */
diff --git a/src/main.c b/src/main.c
index 31dbf45..c247f3c 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,4 +1,27 @@
+#include "gpu.h"
+#include "psxregs.h"
+
+static struct gpu_gvert triangle[] = {
+	{0xff0000, 160, 16}, {0x00ff00, 32, 180}, {0x0000ff, 280, 220}
+};
+
+int dbg;
+
 int main(void)
 {
+	gpu_reset();
+	gpu_setmode(320, 264, 15, 50);
+	gpu_display(1);
+
+	REG_GP0 = GPCMD(GP0_TEXPG) | TEXPG_DRAWDISP | TEXPG_DITHER;
+
+	gpu_cliprect(0, 0, 320, 264);
+	gpu_origin(0, 0);
+
+	gpu_fillrect(0, 0, 320, 264, 0x003f00);
+
+	gpu_draw_gouraud(GP0_GTRI, triangle, 3);
+
+	for(;;);
 	return 0;
 }
diff --git a/src/psxregs.h b/src/psxregs.h
index dc3a7f1..d3042c3 100644
--- a/src/psxregs.h
+++ b/src/psxregs.h
@@ -1,27 +1,27 @@
 #ifndef PSXREGS_H_
 #define PSXREGS_H_
 
-#define REG_BASE	0x1f800000
-#define REGPTR32(x)	(*(volatile unsigned long*)(REG_BASE | (x)))
-#define REGPTR16(x)	(*(volatile unsigned short*)(REG_BASE | (x)))
+#define REG_BASE		0x1f800000
+#define REGPTR32(x)		(*(volatile unsigned long*)(REG_BASE | (x)))
+#define REGPTR16(x)		(*(volatile unsigned short*)(REG_BASE | (x)))
 
 /* --- GPU --- */
-#define REGN_GP0	0x1810
-#define REGN_GP1	0x1814
+#define REGN_GP0		0x1810
+#define REGN_GP1		0x1814
 #define REGN_GPUREAD	REGN_GP0
 #define REGN_GPUSTAT	REGN_GP1
 
-#define REG_GP0		REGPTR32(REGN_GP0)
-#define REG_GP1		REGPTR32(REGN_GP1)
-#define REG_GPUREAD	REGPTR32(REGN_GPUREAD)
-#define REG_GPUSTAT	REGPTR32(REGN_GPUSTAT)
+#define REG_GP0			REGPTR32(REGN_GP0)
+#define REG_GP1			REGPTR32(REGN_GP1)
+#define REG_GPUREAD		REGPTR32(REGN_GPUREAD)
+#define REG_GPUSTAT		REGPTR32(REGN_GPUSTAT)
 
 /* --- interrupts --- */
-#define REGN_ISTAT	1070h
-#define REGN_IMASK	1074h
+#define REGN_ISTAT		1070h
+#define REGN_IMASK		1074h
 
-#define REG_ISTAT	REGPTR32(REGN_ISTAT)
-#define REG_IMASK	REGPTR32(REGN_IMASK)
+#define REG_ISTAT		REGPTR32(REGN_ISTAT)
+#define REG_IMASK		REGPTR32(REGN_IMASK)
 
 enum {
 	IRQ_VBLANK	= 0x0001,
@@ -37,4 +37,129 @@ enum {
 	IRQ_LPEN	= 0x0400
 };
 
+#define GPCMD(cmd)	((cmd) << 24)
+
+enum {
+	GP1_RESET		= 0,
+	GP1_RESET_CMDBUF = 0x01,
+	GP1_IACK		= 0x02,
+	GP1_DISPEN		= 0x03,	/* 0:on, 1:off */
+	GP1_DMADIR		= 0x04,	/* 0:off, 1:fifo, 2:cpu->gpu, 3:gpu->cpu */
+	GP1_START		= 0x05,	/* bits [0,9]: X, [10,18]: Y */
+	GP1_HDISP		= 0x06,	/* (pix*8) bits [0,11]: left, [12,23]: right */
+	GP1_VDISP		= 0x07,	/* bits [0,9]: top, [10,19]: bottom */
+	GP1_DISPMODE	= 0x08,	/* see DISP_* flags */
+};
+
+#define DISP_H256	0
+#define DISP_H320	0x01
+#define DISP_H512	0x02
+#define DISP_H640	0x03
+#define DISP_V240	0
+#define DISP_V480	0x04
+#define DISP_NTSC	0
+#define DISP_PAL	0x08
+#define DISP_15BPP	0
+#define DISP_24BPP	0x10
+#define DISP_ILACE	0x20
+#define DISP_H368	0x40
+
+
+/* primitive bits for GP0 drawing commands */
+enum {
+	PRIM_TRI		= 0x20,
+	PRIM_QUAD		= 0x28,
+	PRIM_LINE		= 0x40,
+	PRIM_PLINE		= 0x48,
+	PRIM_RECT		= 0x60,
+	PRIM_POINT		= 0x6a,	/* rect 1x1 */
+	PRIM_RECT8		= 0x70,
+	PRIM_RECT16		= 0x78,
+
+	PRIM_NOMOD		= 0x01,	/* no-modulate tex/color bit */
+	PRIM_ST			= 0x02,	/* semi-transparent bit */
+	PRIM_TEX		= 0x04,	/* textured bit */
+	PRIM_GOURAUD	= 0x10	/* gouraud bit */
+};
+
+enum {
+	GP0_CLEAR_CACHE	= 0,
+	GP0_FILLRECT	= 0x02,	/* color24+cmd/topleft/size */
+	GP0_BLT_VIDVID	= 0x80,	/* cmd/src/dst/size */
+	GP0_BLT_CPUVID	= 0xa0,	/* cmd/dst/size/data(dma?) */
+	GP0_BLT_VIDCPU	= 0xc0,	/* cmd/src/size/data(GPUREAD|dma) */
+	GP0_TEXPG		= 0xe1,
+	GP0_TEXWIN		= 0xe2,
+	GP0_CLIP_TL		= 0xe3,
+	GP0_CLIP_BR		= 0xe4,
+	GP0_ORIGIN		= 0xe5,
+
+	/* flat tri/quad: cmd+color/v0/.../vN (16+16 YYYYXXXX) */
+	GP0_TRI				= PRIM_TRI,
+	GP0_TRI_ST			= PRIM_TRI | PRIM_ST,
+	GP0_QUAD			= PRIM_QUAD,
+	GP0_QUAD_ST			= PRIM_QUAD | PRIM_ST,
+	/* textured tri/quad: cmd+color/v0/uv0+pal/v1/uv1+texpage/v2/uv2/.. */
+	GP0_TRI_TEXMOD		= PRIM_TRI | PRIM_TEX,
+	GP0_TRI_TEX			= PRIM_TRI | PRIM_TEX | PRIM_NOMOD,
+	GP0_TRI_ST_TEXMOD	= PRIM_TRI | PRIM_ST | PRIM_TEX,
+	GP0_TRI_ST_TEX		= PRIM_TRI | PRIM_ST | PRIM_TEX | PRIM_NOMOD,
+	GP0_QUAD_TEXMOD		= PRIM_QUAD | PRIM_TEX,
+	GP0_QUAD_TEX		= PRIM_QUAD | PRIM_TEX | PRIM_NOMOD,
+	GP0_QUAD_ST_TEXMOD	= PRIM_QUAD | PRIM_ST | PRIM_TEX,
+	GP0_QUAD_ST_TEX		= PRIM_QUAD | PRIM_ST | PRIM_TEX | PRIM_NOMOD,
+	/* gouraud tri/quad: cmd+color0/v0/c1/v1/.../cN/vN */
+	GP0_GTRI			= PRIM_TRI | PRIM_GOURAUD,
+	GP0_GTRI_ST			= PRIM_TRI | PRIM_GOURAUD | PRIM_ST,
+	GP0_GQUAD			= PRIM_QUAD | PRIM_GOURAUD,
+	GP0_GQUAD_ST		= PRIM_QUAD | PRIM_GOURAUD | PRIM_ST,
+	/* gouraud tex tri/quad: cmd+color0/v0/uv0+pal/c1/v1/uv1+texpage/c2/v2/uv2/... */
+	GP0_GTRI_TEXMOD		= PRIM_TRI | PRIM_GOURAUD | PRIM_TEX,
+	GP0_GTRI_ST_TEXMOD	= PRIM_TRI | PRIM_GOURAUD | PRIM_ST | PRIM_TEX,
+	GP0_GQUAD_TEXMOD	= PRIM_QUAD | PRIM_GOURAUD | PRIM_TEX,
+	GP0_GQUAD_ST_TEXMOD	= PRIM_QUAD | PRIM_GOURAUD | PRIM_ST | PRIM_TEX,
+
+	/* line/poly-line: cmd+color/v0/.../vN/PLINE_END(55555555h) */
+	GP0_LINE			= PRIM_LINE,
+	GP0_LINE_ST			= PRIM_LINE | PRIM_ST,
+	GP0_PLINE			= PRIM_PLINE,
+	GP0_PLINE_ST		= PRIM_PLINE | PRIM_ST,
+	/* line/poly-line: cmd+color0/v0/c1/v1/.../cN/vN/PLINE_END */
+	GP0_GLINE			= PRIM_LINE | PRIM_GOURAUD,
+	GP0_GLINE_ST		= PRIM_LINE | PRIM_GOURAUD | PRIM_ST,
+	GP0_GPLINE			= PRIM_PLINE | PRIM_GOURAUD,
+	GP0_GPLINE_ST		= PRIM_PLINE | PRIM_GOURAUD | PRIM_ST,
+
+	/* rect: cmd+col/pos/size(for variable rect) */
+	GP0_RECT			= PRIM_RECT,
+	GP0_RECT_ST			= PRIM_RECT | PRIM_ST,
+	GP0_POINT			= PRIM_POINT,
+	GP0_POINT_ST		= PRIM_POINT | PRIM_ST,
+	GP0_RECT8			= PRIM_RECT8,
+	GP0_RECT8_ST		= PRIM_RECT8 | PRIM_ST,
+	GP0_RECT16			= PRIM_RECT16,
+	GP0_RECT16_ST		= PRIM_RECT16 | PRIM_ST,
+	/* rect: cmd+col/pos/uv0+pal/size(for var rect), texpage in GP0(e1h) */
+	GP0_RECT_TEXMOD		= PRIM_RECT | PRIM_TEX,
+	GP0_RECT_TEX		= PRIM_RECT | PRIM_TEX | PRIM_NOMOD,
+	GP0_RECT_ST_TEXMOD	= PRIM_RECT | PRIM_ST | PRIM_TEX,
+	GP0_RECT_ST_TEX		= PRIM_RECT | PRIM_ST | PRIM_TEX | PRIM_NOMOD,
+	/* ... TODO and the rest ... */
+};
+
+
+enum {
+	TEXPG_BLEND_HALF	= 0,
+	TEXPG_BLEND_ADD		= 0x0020,
+	TEXPG_BLEND_SUB		= 0x0040,
+	TEXPG_BLEND_QUART	= 0x0060,
+	TEXPG_8BPP			= 0x0080,
+	TEXPG_15BPP			= 0x0100,
+	TEXPG_DRAWDISP		= 0x0200,
+	TEXPG_DITHER		= 0x0400,
+	TEXPG_NOTEX			= 0x0800,
+	TEXPG_XFLIP			= 0x1000,
+	TEXPG_YFLIP			= 0x2000
+};
+
 #endif	/* PSXREGS_H_ */
diff --git a/src/startup.S b/src/startup.S
index a058ea5..27935ef 100644
--- a/src/startup.S
+++ b/src/startup.S
@@ -8,56 +8,30 @@
 	.section .startup
 
 	.extern main
+	.extern _stacktop
+	.extern _gp
+	.extern _bss_start
+	.extern _bss_end
 
 	.globl _start
 _start:
-	lui a0, REG_BASE
+	la sp, _stacktop
+	la gp, _gp
 
-	# setup screen mode
-	sw zero, REG_GP1(a0)	# GP1 0: reset
-
-	li t0, 0x03000000	# GP1 3: display enable
-	sw t0, REG_GP1(a0)
-	li t0, 0x08000009	# GP1 8: display mode (320x240 15bpp PAL)
-	sw t0, REG_GP1(a0)
-	li t0, 0x06c60260	# GP1 6: horiz. display range (608-3168)
-	sw t0, REG_GP1(a0)
-	li t0, 0x07049c1f	# GP1 7: vert. display range (31-295)
-	sw t0, REG_GP1(a0)
-
-	li t0, 0xe1000600	# GP0 e1: draw mode (draw allowed & dither enable)
-	sw t0, REG_GP0(a0)
-	li t0, 0xe3000000	# draw area top left (0, 0)
-	sw t0, REG_GP0(a0)
-	li t0, 0xe4041d3f	# draw area bottom right (319,263)
-	sw t0, REG_GP0(a0)
-	li t0, 0xe5000000	# draw offset (0, 0)
-	sw t0, REG_GP0(a0)
-
-	# clear screen
-	li t0, 0x02302010	# cmd 2: fill area (BBGGRR)
-	sw t0, REG_GP0(a0)
-	sw zero, REG_GP0(a0)	# ... top left 0,0 (YYYYXXXX)
-	li t0, 0x0108013f	# ... size 319x239 (HHHHWWWW)
-	sw t0, REG_GP0(a0)
-
-	# draw gouraud triangle
-	li t0, 0x30ff0000	# cmd 30: draw gouraud triangle (+BBGGRR vert0)
-	sw t0, REG_GP0(a0)
-	li t0, 160 | (16 << 16)	# ... vertex(160, 16)
-	sw t0, REG_GP0(a0)
-
-	li t0, 0x0000ff00	# ... color vert1
-	sw t0, REG_GP0(a0)
-	li t0, 32 | (180 << 16)	# ... vertex(32, 180)
-	sw t0, REG_GP0(a0)
-
-	li t0, 0x000000ff	# ... color vert2
-	sw t0, REG_GP0(a0)
-	li t0, 280 | (220 << 16) # ... vertex(220, 280)
-	sw t0, REG_GP0(a0)
+	la t0, _bss_start
+	la t1, _bss_end
+	nop
+	beq t0, t1, donebss
+	nop
+zerobss:
+	sw zero, (t0)
+	addi t0, t0, 4
+	nop
+	bne t0, t1, zerobss
+	nop
+donebss:
 
-	#jal main
+	jal main
 	nop
 
 0:	b 0b