1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/vbe.c	Sat Dec 05 07:28:47 2015 +0200
     1.3 @@ -0,0 +1,153 @@
     1.4 +#include <stdio.h>
     1.5 +#include <string.h>
     1.6 +#include "vbe.h"
     1.7 +#include "dpmi.h"
     1.8 +
     1.9 +/* VGA DAC registers used for palette setting in 8bpp modes */
    1.10 +#define VGA_DAC_STATE		0x3c7
    1.11 +#define VGA_DAC_ADDR_RD		0x3c7
    1.12 +#define VGA_DAC_ADDR_WR		0x3c8
    1.13 +#define VGA_DAC_DATA		0x3c9
    1.14 +
    1.15 +#define MODE_LFB	(1 << 14)
    1.16 +
    1.17 +
    1.18 +struct vbe_info *vbe_get_info(void)
    1.19 +{
    1.20 +	static unsigned short info_block_seg;
    1.21 +	static struct vbe_info *info;
    1.22 +	struct dpmi_real_regs regs;
    1.23 +
    1.24 +	if(!info) {
    1.25 +		/* allocate 32 paragraphs (512 bytes) */
    1.26 +		info_block_seg = dpmi_alloc(32);
    1.27 +		info = (struct vbe_info*)(info_block_seg << 4);
    1.28 +	}
    1.29 +
    1.30 +	memcpy(info->sig, "VBE2", 4);
    1.31 +
    1.32 +	memset(&regs, 0, sizeof regs);
    1.33 +	regs.es = info_block_seg;
    1.34 +	regs.eax = 0x4f00;
    1.35 +
    1.36 +	dpmi_real_int(0x10, &regs);
    1.37 +
    1.38 +	return info;
    1.39 +}
    1.40 +
    1.41 +struct vbe_mode_info *vbe_get_mode_info(int mode)
    1.42 +{
    1.43 +	static unsigned short mode_info_seg;
    1.44 +	static struct vbe_mode_info *mi;
    1.45 +	struct dpmi_real_regs regs;
    1.46 +
    1.47 +	if(!mi) {
    1.48 +		/* allocate 16 paragraphs (256 bytes) */
    1.49 +		mode_info_seg = dpmi_alloc(16);
    1.50 +		mi = (struct vbe_mode_info*)(mode_info_seg << 4);
    1.51 +	}
    1.52 +
    1.53 +	memset(&regs, 0, sizeof regs);
    1.54 +	regs.es = mode_info_seg;
    1.55 +	regs.eax = 0x4f01;
    1.56 +	regs.ecx = mode;
    1.57 +	regs.es = mode_info_seg;
    1.58 +
    1.59 +	dpmi_real_int(0x10, &regs);
    1.60 +	if(regs.eax & 0xff00) {
    1.61 +		return 0;
    1.62 +	}
    1.63 +
    1.64 +	return mi;
    1.65 +}
    1.66 +
    1.67 +int vbe_set_mode(int mode)
    1.68 +{
    1.69 +	struct dpmi_real_regs regs;
    1.70 +
    1.71 +	memset(&regs, 0, sizeof regs);
    1.72 +	regs.eax = 0x4f02;
    1.73 +	regs.ebx = mode;
    1.74 +	dpmi_real_int(0x10, &regs);
    1.75 +
    1.76 +	if(regs.eax == 0x100) {
    1.77 +		return -1;
    1.78 +	}
    1.79 +	return 0;
    1.80 +}
    1.81 +
    1.82 +int vbe_set_palette_bits(int bits)
    1.83 +{
    1.84 +	struct dpmi_real_regs regs;
    1.85 +
    1.86 +	memset(&regs, 0, sizeof regs);
    1.87 +	regs.eax = 0x4f08;
    1.88 +	regs.ebx = bits << 8;	/* bits in bh */
    1.89 +	dpmi_real_int(0x10, &regs);
    1.90 +
    1.91 +	if((regs.eax >> 8) & 0xff == 3) {
    1.92 +		return -1;
    1.93 +	}
    1.94 +	return regs.ebx >> 8 & 0xff;	/* new color bits in bh */
    1.95 +}
    1.96 +
    1.97 +/* TODO: implement palette setting through the VBE2 interface for
    1.98 + * non-VGA displays (actually don't).
    1.99 + */
   1.100 +void vbe_set_palette(int idx, int *col, int count, int bits)
   1.101 +{
   1.102 +	int i, shift = 8 - bits;
   1.103 +
   1.104 +	__asm {
   1.105 +		mov dx, VGA_DAC_ADDR_WR
   1.106 +		mov eax, idx
   1.107 +		out dx, al
   1.108 +	}
   1.109 +
   1.110 +	for(i=0; i<count; i++) {
   1.111 +		unsigned char r = *col++;
   1.112 +		unsigned char g = *col++;
   1.113 +		unsigned char b = *col++;
   1.114 +
   1.115 +		if(shift) {
   1.116 +			r >>= shift;
   1.117 +			g >>= shift;
   1.118 +			b >>= shift;
   1.119 +		}
   1.120 +
   1.121 +		__asm {
   1.122 +			mov dx, VGA_DAC_DATA
   1.123 +			mov al, r
   1.124 +			out dx, al
   1.125 +			mov al, g
   1.126 +			out dx, al
   1.127 +			mov al, b
   1.128 +			out dx, al
   1.129 +		}
   1.130 +	}
   1.131 +}
   1.132 +
   1.133 +static unsigned int get_mask(int sz, int pos)
   1.134 +{
   1.135 +	unsigned int i, mask = 0;
   1.136 +
   1.137 +	for(i=0; i<sz; i++) {
   1.138 +		mask |= 1 << i;
   1.139 +	}
   1.140 +	return mask << pos;
   1.141 +}
   1.142 +
   1.143 +void print_mode_info(FILE *fp, struct vbe_mode_info *mi)
   1.144 +{
   1.145 +	fprintf(fp, "resolution: %dx%d\n", mi->xres, mi->yres);
   1.146 +	fprintf(fp, "color depth: %d\n", mi->bpp);
   1.147 +	fprintf(fp, "mode attributes: %x\n", mi->mode_attr);
   1.148 +	fprintf(fp, "bytes per scanline: %d\n", mi->scanline_bytes);
   1.149 +	fprintf(fp, "number of planes: %d\n", (int)mi->num_planes);
   1.150 +	fprintf(fp, "number of banks: %d\n", (int)mi->num_banks);
   1.151 +	fprintf(fp, "mem model: %d\n", (int)mi->mem_model);
   1.152 +	fprintf(fp, "red bits: %d (mask: %x)\n", (int)mi->rmask_size, get_mask(mi->rmask_size, mi->rpos));
   1.153 +	fprintf(fp, "green bits: %d (mask: %x)\n", (int)mi->gmask_size, get_mask(mi->gmask_size, mi->gpos));
   1.154 +	fprintf(fp, "blue bits: %d (mask: %x)\n", (int)mi->bmask_size, get_mask(mi->bmask_size, mi->bpos));
   1.155 +	fprintf(fp, "framebuffer address: %x\n", mi->fb_addr);
   1.156 +}