From c0af8cc560cb8ccf4e9da121d7045007de304f66 Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@member.fsf.org>
Date: Thu, 3 May 2018 08:56:42 +0300
Subject: [PATCH] fixed VBE bugs

---
 src/test/vbetest.c |   34 ++++++++++++++++++++++++++++++----
 src/vbe.c          |   10 +++++++---
 src/video.c        |    5 ++++-
 src/video.h        |    2 ++
 4 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/src/test/vbetest.c b/src/test/vbetest.c
index 177eac3..91a8c8c 100644
--- a/src/test/vbetest.c
+++ b/src/test/vbetest.c
@@ -3,13 +3,15 @@
 #include "video.h"
 #include "asmops.h"
 #include "keyb.h"
+#include "contty.h"
 
 static uint16_t *framebuf;
 
 int vbetest(void)
 {
-	int i, nmodes;
+	int i, j, nmodes;
 	struct video_mode vi;
+	uint16_t *fbptr;
 
 	nmodes = video_mode_count();
 	printf("%d video modes found:\n", nmodes);
@@ -17,20 +19,44 @@ int vbetest(void)
 		if(video_mode_info(i, &vi) == -1) {
 			continue;
 		}
-		printf(" %04x: %dx%d %d bpp (%d%d%d)\n", vi.mode, vi.width, vi.height, vi.bpp,
-				vi.rbits, vi.gbits, vi.bbits);
+		printf(" %04x: %dx%d %d bpp", vi.mode, vi.width, vi.height, vi.bpp);
+		if(vi.bpp > 8) {
+			printf(" (%d%d%d)\n", vi.rbits, vi.gbits, vi.bbits);
+		} else {
+			putchar('\n');
+		}
 	}
 
 	if(!(framebuf = set_video_mode(find_video_mode(640, 480, 16)))) {
 		return -1;
 	}
+	get_color_bits(&vi.rbits, &vi.gbits, &vi.bbits);
+	get_color_shift(&vi.rshift, &vi.gshift, &vi.bshift);
+	get_color_mask(&vi.rmask, &vi.gmask, &vi.bmask);
+
+	fbptr = framebuf;
+	for(i=0; i<480; i++) {
+		for(j=0; j<640; j++) {
+			int xor = i^j;
+			uint16_t r = xor & 0xff;
+			uint16_t g = (xor << 1) & 0xff;
+			uint16_t b = (xor << 2) & 0xff;
+
+			r >>= 8 - vi.rbits;
+			g >>= 8 - vi.gbits;
+			b >>= 8 - vi.bbits;
 
-	memset(framebuf, 0xff, 640 * 240 * 2);
+			*fbptr++ = ((r << vi.rshift) & vi.rmask) | ((g << vi.gshift) & vi.gmask) |
+				((b << vi.bshift) & vi.bmask);
+		}
+	}
 
+	while(kb_getkey() != -1);
 	while(kb_getkey() == -1) {
 		halt_cpu();
 	}
 
 	set_vga_mode(3);
+	con_clear();
 	return 0;
 }
diff --git a/src/vbe.c b/src/vbe.c
index d4847d2..933ffe5 100644
--- a/src/vbe.c
+++ b/src/vbe.c
@@ -16,15 +16,19 @@ struct vbe_info *vbe_get_info(void)
 	struct vbe_info *info;
 	struct int86regs regs;
 
+	printf("vbe_get_info... ");
+
 	info = (struct vbe_info*)low_mem_buffer;
 
 	memcpy(info->sig, "VBE2", 4);
 
 	memset(&regs, 0, sizeof regs);
-	regs.es = (uint32_t)low_mem_buffer >> 4;
+	regs.es = (uint32_t)info >> 4;
 	regs.eax = 0x4f00;
 	int86(0x10, &regs);
 
+	printf("status: %d\n", (regs.eax >> 8) & 0xff);
+
 	if((regs.eax & 0xffff) != 0x4f) {
 		return 0;
 	}
@@ -37,10 +41,10 @@ struct vbe_mode_info *vbe_get_mode_info(int mode)
 	struct vbe_mode_info *mi;
 	struct int86regs regs;
 
-	mi = (struct vbe_mode_info*)low_mem_buffer;
+	mi = (struct vbe_mode_info*)(low_mem_buffer + 512);
 
 	memset(&regs, 0, sizeof regs);
-	regs.es = (uint32_t)low_mem_buffer >> 4;
+	regs.es = (uint32_t)mi >> 4;
 	regs.eax = 0x4f01;
 	regs.ecx = mode;
 	int86(0x10, &regs);
diff --git a/src/video.c b/src/video.c
index 58b764b..d926107 100644
--- a/src/video.c
+++ b/src/video.c
@@ -89,7 +89,7 @@ static int init_once(void)
 void *set_video_mode(int mode)
 {
 	if(init_once() == -1) return 0;
-	if(mode < 0 || mode >= mode_count) return 0;
+	if(mode < 0) return 0;
 
 	if(!(mode_info = vbe_get_mode_info(mode))) {
 		return 0;
@@ -150,6 +150,9 @@ int video_mode_info(int n, struct video_mode *vid)
 	vid->rbits = inf->rmask_size;
 	vid->gbits = inf->gmask_size;
 	vid->bbits = inf->bmask_size;
+	vid->rshift = inf->rpos;
+	vid->gshift = inf->gpos;
+	vid->bshift = inf->bpos;
 	vid->rmask = color_mask(inf->rmask_size, inf->rpos);
 	vid->gmask = color_mask(inf->gmask_size, inf->gpos);
 	vid->bmask = color_mask(inf->bmask_size, inf->bpos);
diff --git a/src/video.h b/src/video.h
index 3e4626d..bf42f53 100644
--- a/src/video.h
+++ b/src/video.h
@@ -23,6 +23,7 @@ struct video_mode {
 	int width, height;
 	int bpp;
 	int rbits, gbits, bbits;
+	int rshift, gshift, bshift;
 	unsigned int rmask, gmask, bmask;
 };
 
@@ -36,6 +37,7 @@ int video_mode_info(int n, struct video_mode *vid);
 
 int get_color_bits(int *rbits, int *gbits, int *bbits);
 int get_color_mask(unsigned int *rmask, unsigned int *gmask, unsigned int *bmask);
+int get_color_shift(int *rshift, int *gshift, int *bshift);
 
 /* defined in video_asm.s */
 void wait_vsync(void);
-- 
1.7.10.4