diff options
Diffstat (limited to 'xxx/boot2/disk_load_16.asm')
| -rw-r--r-- | xxx/boot2/disk_load_16.asm | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/xxx/boot2/disk_load_16.asm b/xxx/boot2/disk_load_16.asm new file mode 100644 index 0000000..65b1bff --- /dev/null +++ b/xxx/boot2/disk_load_16.asm @@ -0,0 +1,281 @@ +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;; Miguel's FoolOS Helper Functions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +; +;disk_load_16 +; + +[bits 16] + +STR_ERROR: + db "Disk Read Error",0 + +STR_SPACE: + db " ",0 + +STR_OK: + db "Kernel Loaded",0 +STR_PROGRESS: + db ".",0 + +bpbSectorsPerTrack: + dw 18 + +bpbHeadsPerCylinder: + dw 2 + +LBA: + dw 10 ; current lba + +disk_load_16: + + ; check if LBA is supported + mov ah,0x41 + mov bx,0x55aa + int 0x13 + jnc disk_load_lba + jmp disk_load_chs + + +;####################### + +disk_load_lba: + + pusha + + mov bx,0x1800 ;target es:bx + mov es,bx + mov bx,0 + + next_sectors_lba: + + jmp skip_debug_lba + ;show es - target + pusha + mov bx,es + + ;mov al,bh + ;call print_hex_byte + + ;mov al,bl + ;call print_hex_byte + + mov bx,[LBA] + + mov al,bh + call print_hex_byte + + mov al,bl + call print_hex_byte + + popa + ;-- + + skip_debug_lba: + + mov [lba_addr_sector],es + mov ax,[LBA] + mov [lba_first_sector],ax + + mov dl,[BOOT_DRIVE] + + mov ah,0x42 + mov bx,0 + mov ds,bx + lea si,[lba_adr] + int 0x13 + jc disk_read_error + + mov bx,es + add bx,0x0800 + + mov ax,[LBA] + add ax,64 ; 64 sectors = 0x2000*4 bytes + mov [LBA],ax + + cmp bx,0x9000 + je disk_load_finish + + mov es,bx ;next target es:bx + mov bx,0 + + jmp next_sectors_lba + +;####################### + + +disk_load_chs: + + pusha + + ; get boot drive geometry + mov ah,8 + mov dl,[BOOT_DRIVE] + int 0x13 + + add dh,1 + and cl,0x3f + + mov [bpbSectorsPerTrack],cl + mov [bpbHeadsPerCylinder],dh + ; + + ;show geometry + mov al,dh + call print_hex_byte + + mov bx, STR_SPACE + call print_string + + mov al,cl + call print_hex_byte + + call print_nextline + popa + ; + + pusha + + + mov bx,0x1800 ;target es:bx + mov es,bx + mov bx,0 + + next_sectors_chs: + + ;jmp skip_debug + pusha + + mov bx, STR_SPACE + call print_string + + ;show es - target + mov bx,es + + mov al,bh + call print_hex_byte + + mov al,bl + call print_hex_byte + + mov bx, STR_SPACE + call print_string + + ;show next LBA numer + mov ax,[LBA] + mov al,ah + call print_hex_byte + + mov ax,[LBA] + call print_hex_byte + + mov bx, STR_SPACE + call print_string + + popa + + mov ax,[LBA] + + ;calculate chs + call lba_to_chs + + ;show chs sector/ head / cylinder + mov al,cl + call print_hex_byte + + mov al,dh + call print_hex_byte + + mov al,ch + call print_hex_byte + + call print_nextline + + skip_debug: + + + mov ax,[LBA] + + ;calculate chs + call lba_to_chs + + ; and now READ it! + mov al,1 ;number of sectors to read + mov dl,[BOOT_DRIVE] + + mov ah,0x02 ;BIOS read sector func + int 0x13 ;bios interrupt + + jc disk_read_error + + mov bx,es + add bx,0x0020 + cmp bx,0x9000 + je disk_load_finish + + mov es,bx + mov bx,0 + + mov ax,[LBA] + add ax,1 + mov [LBA],ax + + jmp next_sectors_chs + +disk_read_error: + mov bx, STR_ERROR + call print_string + call print_nextline + ;jmp $ + +disk_load_finish: + + mov bx, STR_PROGRESS + call print_string +; call print_nextline + + popa + ret + + + +;lba to chs translation: +; input : ax - lba +; output: cl - sector +; dh - head +; ch - cylinder / track + +lba_to_chs: + + xor dx, dx ; prepare dx:ax for operation + div WORD [bpbSectorsPerTrack] ; divide by sectors per track + inc dl ; add 1 (obsolute sector formula) + mov cl, dl + + xor dx, dx ; prepare dx:ax for operation + div WORD [bpbHeadsPerCylinder] ; mod by number of heads (Absolue head formula) + mov dh,dl ; everything else was already done from the first formula + + mov ch, al ; not much else to do :) + ret + +;; here we hold the lba addr +lba_adr: + + dw 0x10 ; size of packet ( 16 byte) + dw 64 ; number of sectors to read + + ; target is 0x10000 + + dw 0x0000 ; target addr. offset + +lba_addr_sector: + dw 0x1800 ; target addr. sector + +lba_first_sector: + dw 10 ; first sector to read + dw 0 + + dd 0 + + ; |