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#include <string.h>
#include <dev/vesa.h>
#include <dev/v86.h>
// ---- VESA data structures
typedef struct {
char vbe_signature[4]; // == "VESA"
uint16_t vbe_version;
v86_farptr_t oem_string_ptr;
uint8_t capabilities[4];
v86_farptr_t video_mode_ptr;
uint16_t total_memory; // as # of 64KB blocks
} __attribute__((packed)) vbe_info_block_t;
typedef struct {
uint16_t attributes;
uint8_t winA, winB;
uint16_t granularity;
uint16_t winsize;
uint16_t segmentA, segmentB;
v86_farptr_t real_fct_ptr;
uint16_t pitch; // bytes per scanline
uint16_t Xres, Yres;
uint8_t Wchar, Ychar, planes, bpp, banks;
uint8_t memory_model, bank_size, image_pages;
uint8_t reserved0;
uint8_t red_mask, red_position;
uint8_t green_mask, green_position;
uint8_t blue_mask, blue_position;
uint8_t rsv_mask, rsv_position;
uint8_t directcolor_attributes;
uint32_t physbase; // the offset of the framebuffer in physical memory!
uint32_t reserved1;
uint16_t reserved2;
} __attribute__((packed)) vbe_mode_info_block_t;
// ---- VESA code
void vesa_detect(fs_t *iofs) {
if (!v86_begin_session()) return;
vbe_info_block_t *i = (vbe_info_block_t*)v86_alloc(512);
memset(i, 0, 512);
strncpy(i->vbe_signature, "VBE2", 4);
v86_regs.ax = 0x4F00;
v86_regs.es = V86_SEG_OF_LIN(i);
v86_regs.di = V86_OFF_OF_LIN(i);
if (v86_bios_int(0x10)) {
if (v86_regs.ax == 0x004F) {
dbg_printf("Detected VESA (sig %s, ver 0x%x, oem %s) with %d kb ram.\n",
i->vbe_signature, i->vbe_version, v86_lin_of_fp(i->oem_string_ptr), 64 * i->total_memory);
vbe_mode_info_block_t *mi = (vbe_mode_info_block_t*)v86_alloc(256);
uint16_t *modes = (uint16_t*)v86_lin_of_fp(i->video_mode_ptr);
for (int n = 0; modes[n] != 0xFFFF; n++) {
v86_regs.ax = 0x4F01;
v86_regs.cx = modes[n];
v86_regs.es = V86_SEG_OF_LIN(mi);
v86_regs.di = V86_OFF_OF_LIN(mi);
if (v86_bios_int(0x10) && v86_regs.ax == 0x004F) {
dbg_printf("Mode 0x%x : %dx%dx%d at 0x%p\n", modes[n], mi->Xres, mi->Yres, mi->bpp, mi->physbase);
} else {
dbg_printf("Mode 0x%x : could not get info\n", modes[n]);
}
}
} else {
dbg_printf("Error in BIOS int 0x10/0x4F00.\n");
}
} else {
dbg_printf("Could not call BIOS int 0x10.\n");
}
v86_end_session();
}
/* vim: set ts=4 sw=4 tw=0 noet :*/
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