207 lines
2.9 KiB
NASM
207 lines
2.9 KiB
NASM
cpu 8086
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org 0x0000
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rom:
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db 0x55, 0xAA
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.sectors:
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db 0x00
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.init:
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mov dx, isr_debug
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mov al, 0x1
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call intr_register
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mov al, 0x03
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call intr_register
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retf
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.name:
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db "rDebug", 0
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times (0x18 - ($-$$)) db 0
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.pcir_ptr:
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dw 0
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times (0x1A - ($-$$)) db 0
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.pnp_ptr:
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dw pnp
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pnp:
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db "$PnP"
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.version:
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db 1 ; version 1
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.length:
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db 2 ; 2 * 16 length
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dw 0 ; offset of next header
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db 0
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.checksum:
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db 0 ; checksum (filled by fix-rom)
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dd 0 ; device identifier
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dw 0 ; manufacturer string
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dw rom.name ; product name string
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db 0,0,0 ; device type string
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db 0x20 ; device indicator, bit for "read cacheable" set
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dw 0 ; boot connection vector
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dw 0 ; boot disconnect vector
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dw 0 ; bootstrap entry point
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dw 0 ; reserved
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dw 0
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putc:
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push bx
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push cx
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mov ah, 0x0e
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mov bx, 0x0000
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int 0x10
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pop cx
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pop bx
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ret
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intr_register:
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; DI = AL * 4
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mov ah, 4
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mul ah
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mov di, ax
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; ES = 0
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xor ax, ax
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mov es, ax
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; store offset
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mov ax, dx
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stosw
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; store segment
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mov ax, cs
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stosw
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ret
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; Names for words in debug frame
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; Two characters per word, 14 words total
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debug_frame_names:
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; general-purpose registers
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db "AXCXDXBXSPBPSIDI"
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; extra registers
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db "DSESSSIPCSFL"
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; Names for bits in debug_frame+26 (FL/Flags register)
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; One character per bit, 16 bits total
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debug_frame_flags:
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db "++++ODIT"
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db "SZ+A+P+C"
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; Print a single register from the frame
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; in SI frame offset for register
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debug_frame_register_print:
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mov bx, debug_frame_names
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mov al, [cs:bx+si] ; first name char load
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call putc
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mov al, [cs:bx+si+1] ; second name char load
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call putc
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mov al, '='
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call putc
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mov ax, [ss:bp+si] ; value load
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; prepare call to print_number
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push bx
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push cx
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mov bx, 0x0010
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mov cx, 3
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call print_number_padded
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pop cx
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pop bx
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mov al, ' '
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call putc
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ret
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debug_frame_print:
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mov si, 0
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mov cx, 8
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.reg1loop:
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call debug_frame_register_print
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add si, 2
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loop .reg1loop
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mov dx, [ss:bp+26]
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mov di, debug_frame_flags
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mov cx, 0x0010
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.flag_loop:
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mov al, [cs:di]
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inc di
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cmp al, '+'
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je .next
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test dx, 0x8000
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jnz .write
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mov al, '-'
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.write:
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call putc
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.next:
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sal dx, 1
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loop .flag_loop
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call printf
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db 0x0A, 0x0D, 0
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mov si, 16
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mov cx, 3
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.reg2loop:
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call debug_frame_register_print
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add si, 2
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loop .reg2loop
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mov ax, [bp+24]
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mov bx, 0x0010
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mov cx, 3
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call print_number_padded
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mov al, ':'
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call putc
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mov ax, [bp+22]
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mov bx, 0x0010
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mov cx, 3
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call print_number_padded
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call printf
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db 0x0A, 0x0D, 0
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ret
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; this prints registers
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; expect to be called as interrupt routine
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isr_debug:
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push ss
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push es
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push ds
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push di
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push si
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push bp
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push sp
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push bx
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push dx
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push cx
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push ax
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mov bp, sp
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mov [bp+08], bp
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add WORD [bp+08], 28
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call printf
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db 0x0A, 0x0D, 0
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call debug_frame_print
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pop ax
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pop cx
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pop dx
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pop bx
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pop bp
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pop bp
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pop si
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pop di
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pop ds
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pop es
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pop ss
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iret
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%include "printf.asm"
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align 512
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