| 10,26 → 10,32 |
|---|
| times 57h db 0 |
| ; file 'bt2.dat':3,57h |
| @@: |
| cmp byte [si], 80h |
| jnz @f |
| mov eax, [si+8] |
| mov [cs:7C1Ch], eax |
| @@: |
| xor eax, eax |
| mov ds, ax |
| mov ss, ax |
| mov sp, 7C00h |
| mov bp, sp |
| mov [boot_drive], dl |
| cld |
| sti |
| push 800h |
| pop es |
| movzx ebx, word [7C0Eh] ; reserved_sect |
| movzx ebx, word [bp+0Eh] ; reserved_sect |
| mov [fat_start], ebx |
| mov al, byte [7C10h] ; num_fats |
| mul dword [7C24h] ; sect_fat |
| mov al, byte [bp+10h] ; num_fats |
| mul dword [bp+24h] ; sect_fat |
| add eax, ebx |
| ; cluster 2 begins from sector eax |
| movzx ebx, byte [7C0Dh] ; sects_per_clust |
| movzx ebx, byte [bp+0Dh] ; sects_per_clust |
| add bx, bx |
| sub eax, ebx |
| mov [data_start], eax |
| mov eax, [7C2Ch] ; root_cluster |
| mov eax, [bp+2Ch] ; root_cluster |
| and eax, 0FFFFFFFh |
| fat32_parse_dir: |
| xor bx, bx |
| 36,7 → 42,7 |
|---|
| mov di, bx |
| push eax |
| call read_cluster |
| movzx cx, byte [7C0Dh] ; sects_per_clust |
| movzx cx, byte [bp+0Dh] ; sects_per_clust |
| shl cx, 4 ; *0x200/0x20 |
| scan_cluster: |
| cmp byte [es:di], 0 |
| 65,7 → 71,7 |
|---|
| push eax |
| call read_cluster |
| mov ax, es |
| movzx cx, byte [7C0Dh] |
| movzx cx, byte [bp+0Dh] |
| shl cx, 5 |
| add ax, cx |
| mov es, ax |
| 82,7 → 88,7 |
|---|
| |
| read_cluster: |
| ; in: eax = cluster, bx->buffer |
| movzx ecx, byte [7C0Dh] |
| movzx ecx, byte [bp+0Dh] |
| mul ecx |
| add eax, [data_start] |
| |
| 91,7 → 97,7 |
|---|
| ; cx = number of sectors |
| ; es:bx -> buffer |
| read: |
| add eax, [7C1Ch] ; hidden sectors |
| add eax, [bp+1Ch] ; hidden sectors |
| push es |
| read_loop: |
| pushad |