diff options
Diffstat (limited to 'tools/firmware/vgabios/vbe.c')
| -rw-r--r-- | tools/firmware/vgabios/vbe.c | 30 |
1 files changed, 28 insertions, 2 deletions
diff --git a/tools/firmware/vgabios/vbe.c b/tools/firmware/vgabios/vbe.c index 3fc786d851..04b1be48f5 100644 --- a/tools/firmware/vgabios/vbe.c +++ b/tools/firmware/vgabios/vbe.c @@ -742,6 +742,29 @@ no_vbe_flag: jmp _display_string ASM_END +ASM_START +_size64: + push bp + mov bp, sp + push dx + +; multiply bbp by yres first as results fit in 16bits +; then multiply by xres + mov ax, 8[bp] + mul word 6[bp] + mul word 4[bp] +; divide by 2^19 ceiling result + add ax, #0xffff + adc dx, #7 + mov ax, dx + shr ax, #3 + + pop dx + pop bp + ret +ASM_END + + /** Function 00h - Return VBE Controller Information * * Input: @@ -844,9 +867,12 @@ Bit16u *AX;Bit16u ES;Bit16u DI; do { + Bit16u size_64k = size64(cur_info->info.XResolution, cur_info->info.YResolution, cur_info->info.BitsPerPixel); + Bit16u max_bpp = dispi_get_max_bpp(); + if ((cur_info->info.XResolution <= dispi_get_max_xres()) && - (cur_info->info.BitsPerPixel <= dispi_get_max_bpp()) && - (cur_info->info.XResolution * cur_info->info.XResolution * cur_info->info.BitsPerPixel <= vbe_info_block.TotalMemory << 19 )) { + (cur_info->info.BitsPerPixel <= max_bpp) && + (size_64k <= vbe_info_block.TotalMemory)) { #ifdef DEBUG printf("VBE found mode %x => %x\n", cur_info->mode,cur_mode); #endif |