diff options
| author | Kartik Agaram <vc@akkartik.com> | 2020-12-26 21:21:07 -0800 |
|---|---|---|
| committer | Kartik Agaram <vc@akkartik.com> | 2020-12-26 21:23:04 -0800 |
| commit | a0aecc8267084807ece1affaf01559d998c325c4 (patch) | |
| tree | b379ec827d301259d468877326a3e633817c5ddf /baremetal/boot.hex | |
| parent | a7ae16ed066fd86e84ea5d2f129ec641579eed1f (diff) | |
| download | mu-a0aecc8267084807ece1affaf01559d998c325c4.tar.gz | |
7415 - baremetal: locate the linear frame buffer
0xa0000 only contains a single bank's worth of memory-mapped video RAM. The LFB is supposed to have everything.
Diffstat (limited to 'baremetal/boot.hex')
| -rw-r--r-- | baremetal/boot.hex | 61 |
1 files changed, 55 insertions, 6 deletions
diff --git a/baremetal/boot.hex b/baremetal/boot.hex index 25c172f8..4c4e3044 100644 --- a/baremetal/boot.hex +++ b/baremetal/boot.hex @@ -102,6 +102,15 @@ cd 10 # int 10h, Vesa BIOS extensions # 43: + # load information for the (hopefully) current video mode + # mostly just for the address to the linear frame buffer + b4 4f # ah <- 4f (VBE) + b0 01 # al <- 01 (get video mode) + b9 07 01 00 00 # ecx <- 0x0107 (mode we requested) + bf 40 7d 00 00 # edi <- 0x7d40 (video mode info) + cd 10 + +# 53: # switch to 32-bit mode 0f 01 16 # lgdt 00/mod/indirect 010/subop 110/rm/use-disp16 a0 7c # *gdt_descriptor @@ -111,10 +120,9 @@ ea e0 7c 08 00 # far jump to initialize_32bit_mode after setting cs to the record at offset 8 in the gdt (gdt_code) # padding -# 57: +# 67: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 -00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ## GDT: 3 records of 8 bytes each @@ -238,13 +246,54 @@ e9 fb ff # loop forever cf # iret # padding -# 12f +# 12f: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + +# 140: +# video mode info: + 00 00 # attributes + 00 # winA + 00 # winB +# 144 + 00 00 # granularity + 00 00 # winsize +# 148 + 00 00 # segmentA + 00 00 # segmentB +# 14c + 00 00 00 00 # realFctPtr (who knows) +# 150 + 00 00 # pitch + 00 00 # Xres +# 154 + 00 00 # Yres + 00 00 # Wchar Ychar +# 158 + 00 # planes + 00 # bpp + 00 # banks + 00 # memory_model +# 15c + 00 # bank_size + 00 # image_pages + 00 # reserved +# 15f + 00 00 # red_mask red_position + 00 00 # green_mask green_position + 00 00 # blue_mask blue_position + 00 00 # rsv_mask rsv_position + 00 # directcolor_attributes +# 168 + 00 00 00 00 # physbase <== linear frame buffer + +# reserved +# 16c: + 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 -00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 -00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 -00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + +# padding +# 180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |