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| author | Kartik K. Agaram <vc@akkartik.com> | 2021-05-29 17:23:04 -0700 |
|---|---|---|
| committer | Kartik K. Agaram <vc@akkartik.com> | 2021-05-29 17:23:04 -0700 |
| commit | 9516dfa0b04bcdcd1c9c38aa6278549ccdb5528c (patch) | |
| tree | a701a0435d01d0a24a258c8ed06a7d9c836b2890 /boot.subx | |
| parent | d85529f3fac9044cfc52d395b1b64de4f4901cb9 (diff) | |
| download | mu-9516dfa0b04bcdcd1c9c38aa6278549ccdb5528c.tar.gz | |
shell: skeleton for scrolling
Diffstat (limited to 'boot.subx')
| -rw-r--r-- | boot.subx | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/boot.subx b/boot.subx index 8ad3f2a8..7baf88e8 100644 --- a/boot.subx +++ b/boot.subx @@ -122,6 +122,20 @@ cd/syscall 0x13/imm8/bios-disk-services 0f 82/jump-if-carry disk_error/disp16 + # load two more tracks of disk into addresses [0x46c00, 0x56800) + b4/copy-to-ah 2/imm8/read-drive + # dl comes conveniently initialized at boot time with the index of the device being booted + b5/copy-to-ch 0/imm8/cylinder + b6/copy-to-dh 6/imm8/head + b1/copy-to-cl 1/imm8/sector # 1-based + b0/copy-to-al 0x7e/imm8/num-sectors # 2*63 = 126 + # address to write sectors to = es:bx = 0x46c00, contiguous with boot segment + bb/copy-to-bx 0x46c0/imm16 + 8e/->seg 3/mod/direct 3/rm32/bx 0/r32/es + bb/copy-to-bx 0/imm16 + cd/syscall 0x13/imm8/bios-disk-services + 0f 82/jump-if-carry disk_error/disp16 + # reset es bb/copy-to-bx 0/imm16 8e/->seg 3/mod/direct 3/rm32/bx 0/r32/es |