diff options
Diffstat (limited to 'apps')
| -rw-r--r-- | apps/boot.hex | 61 |
1 files changed, 48 insertions, 13 deletions
diff --git a/apps/boot.hex b/apps/boot.hex index 60b91cf6..fe1fdada 100644 --- a/apps/boot.hex +++ b/apps/boot.hex @@ -1,7 +1,7 @@ # Bootable image that: # - loads more sectors past the first boot sector (using BIOS primitives) # - switches to 32-bit mode (giving up access to BIOS primitives) -# - as an example program, prints 'H' to the top-left of the screen (by writing to memory-mapped VGA memory) +# - as an example program, prints a letter from the second sector to the top-left of the screen (by writing to memory-mapped VGA memory) # # If the initial load fails, it prints 'D' to the top-left of the screen and # halts. @@ -147,24 +147,22 @@ e9 fb ff # loop forever # f0: # Entry: - # *0xb8000 <- 0x0f48 - c7 # operate on rm32 with imm32 - # modrm - 05 # 00/mod/indirect 000/subop/copy 101/rm32/use-disp32 + # eax <- *0x7e04 # random address in second segment containing 'H' + 8b # copy rm32 to r32 + 05 # 00/mod/indirect 000/r32/eax 101/rm32/use-disp32 + # disp32 + 04 7e 00 00 + # *0xb8000 <- eax + 89 # copy r32 to rm32 + 05 # 00/mod/indirect 000/r32/eax 101/rm32/use-disp32 # disp32 00 80 0b 00 - # imm32 - 48 # 'H' - 0f # white on black - 00 00 e9 fb ff ff ff # loop forever # padding to 512 bytes -# ff: - 00 -# 100: -00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 +# 101: + 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 @@ -183,4 +181,41 @@ e9 fb ff ff ff # loop forever 55 aa # final 2 bytes: boot sector marker +## sector 2 +# not loaded on boot; loaded by load_disk + +# 200: +00 00 00 00 48 0f 00 00 00 00 00 00 00 00 00 00 # spot the 'H' with attributes +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 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 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 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 +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 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 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 00 00 00 00 +00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + # vim:ft=subx |