debug: Split commands into thematically organized files

This commit is contained in:
Nero 2020-05-18 23:43:54 +02:00
parent 8056ad5cfb
commit a31e574b3a
5 changed files with 195 additions and 166 deletions

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@ -1,3 +1,61 @@
; Commands and utils related to displaying or editing memory or registers
cmd_r: cmp byte [si], 0
je printregs
call eat_register
jc .err
mov al, [cs:bx+rnames]
call putc
mov al, [cs:bx+rnames+1]
call putc
call space
call edit_word
call crlf
ret
.err: mov di, eat_register.emsg
jmp parse_error
printregs:
mov cx, 13
xor bx, bx
mov ah, 0x0e
mov si, reg_ax
.loop: push cx
mov dx, [cs:si+rnames]
lodsw
call printreg
pop cx
loop .loop
mov dx, [reg_fl]
mov si, fnames
mov cx, 16
.floop: mov al, [cs:si]
inc si
cmp al, '+'
je .fskip
test dx, 0x8000
jnz .fprnt
mov al, '-'
.fprnt: int 0x10
.fskip: shl dx, 1
loop .floop
call crlf
ret
printreg:
push ax
mov al, dl
call putc
mov al, dh
call putc
mov al, '='
call putc
pop dx
call print16
call space
ret
; let the user edit the word at ES:BX ; let the user edit the word at ES:BX
edit_word: edit_word:
push bx push bx

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@ -17,23 +17,17 @@ parse_error:
; Advance over whitespace ; Advance over whitespace
; IN DS:SI ; IN DS:SI
eat_whitespace: eat_whitespace:
; peek on next char .loop: lodsb
mov al, [si] cmp al, 0x20
; ES := CS je .loop
push es cmp al, 0x0A
push cs je .loop
pop es cmp al, 0x0D
; string search je .loop
mov di, .chars cmp al, 0x09
mov cx, 4 je .loop
scasb dec si
; restore bss segment ret
pop es
jne .ret
inc si
jmp eat_whitespace
.chars: db 0x09, 0x0A, 0x0D, 0x20
.ret: ret
; Parse a register name ; Parse a register name
; IN DS:SI string to read ; IN DS:SI string to read

83
debug/run.asm Normal file
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@ -0,0 +1,83 @@
; Commands related to executing debugged code
cmd_g: and word [reg_fl+1], 0xfe
jmp return
cmd_t: or word [reg_fl+1], 0x03
jmp return
int3entry:
; save DS and load bss segment from IVT
push ds
mov ds, [cs:zero]
mov ds, [bssvec*4]
; save AX so we can work with it
mov [reg_ax], ax
; pop DS, IP, CS and flags from stack
pop ax
mov [reg_ds], ax
pop ax
mov [reg_ip], ax
pop ax
mov [reg_cs], ax
pop ax
mov [reg_fl], ax
; save the other registers
mov [reg_cx], cx
mov [reg_dx], dx
mov [reg_bx], bx
mov [reg_sp], sp
mov [reg_bp], bp
mov [reg_si], si
mov [reg_di], di
; save other segment registers we can access
mov [reg_ss], ss
mov [reg_es], es
; initialize other segments and setup stack
mov ax, ds
mov es, ax
mov ss, ax
mov sp, stack
call crlf
call printregs
loop: ; show prompt
mov al, '-'
call putc
; read data
mov byte [inmin], 1
mov byte [inmax], 16
mov word [ingetc], getcu
call gets
pushf
call crlf
popf
jc loop
; execute
call runcmd
jmp loop
return: ; restore stack pointer
mov ss, [reg_ss]
mov sp, [reg_sp]
; push flags, CS and IP
mov ax, [reg_fl]
push ax
mov ax, [reg_cs]
push ax
mov ax, [reg_ip]
push ax
; restore GPR
mov ax, [reg_ax]
mov cx, [reg_cx]
mov dx, [reg_dx]
mov bx, [reg_bx]
mov bp, [reg_bp]
mov si, [reg_si]
mov di, [reg_di]
; restore segment registers
; DS must be last
mov es, [reg_es]
mov ds, [reg_ds]
; final jump back
iret

35
debug/util.asm Normal file
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@ -0,0 +1,35 @@
; Utility commands
cmd_h: call eat_whitespace
call eat_hex_word
jc .err
mov bx, dx
call eat_whitespace
call eat_hex_word
jc .err
xchg bx, dx
push dx
add dx, bx
call print16
call space
pop dx
sub dx, bx
call print16
jmp crlf
.err: mov di, eat_hex_word.emsg
jmp parse_error
cmd_?: mov si, .txt
jmp putcs
.txt: db "G Go", 0x0A, 0x0D
db "H w w Add and subtract two values", 0x0A, 0x0D
db "R[r] Print register values", 0x0A, 0x0D
db "T Single-Step", 0x0A, 0x0D
db 0

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@ -57,93 +57,13 @@ init: push ds
pop ds pop ds
retf retf
%include "debug/parse.asm"
%include "debug/chario.asm"
%include "debug/edit.asm"
int3entry:
; save DS and load bss segment from IVT
push ds
mov ds, [cs:zero]
mov ds, [bssvec*4]
; save AX so we can work with it
mov [reg_ax], ax
; pop DS, IP, CS and flags from stack
pop ax
mov [reg_ds], ax
pop ax
mov [reg_ip], ax
pop ax
mov [reg_cs], ax
pop ax
mov [reg_fl], ax
; save the other registers
mov [reg_cx], cx
mov [reg_dx], dx
mov [reg_bx], bx
mov [reg_sp], sp
mov [reg_bp], bp
mov [reg_si], si
mov [reg_di], di
; save other segment registers we can access
mov [reg_ss], ss
mov [reg_es], es
; initialize other segments and setup stack
mov ax, ds
mov es, ax
mov ss, ax
mov sp, stack
call crlf
call printregs
loop: ; show prompt
mov al, '-'
call putc
; read data
mov byte [inmin], 1
mov byte [inmax], 16
mov word [ingetc], getcu
call gets
pushf
call crlf
popf
jc loop
; execute
call runcmd
jmp loop
return: ; restore stack pointer
mov ss, [reg_ss]
mov sp, [reg_sp]
; push flags, CS and IP
mov ax, [reg_fl]
push ax
mov ax, [reg_cs]
push ax
mov ax, [reg_ip]
push ax
; restore GPR
mov ax, [reg_ax]
mov cx, [reg_cx]
mov dx, [reg_dx]
mov bx, [reg_bx]
mov bp, [reg_bp]
mov si, [reg_si]
mov di, [reg_di]
; restore segment registers
; DS must be last
mov es, [reg_es]
mov ds, [reg_ds]
; final jump back
iret
%include "debug/names.asm"
; Expects DI to mark end of command ; Expects DI to mark end of command
runcmd: mov si, inbuf runcmd: mov si, inbuf
lodsb lodsb
cmp al, 'G' cmp al, 'G'
je cmd_g je cmd_g
cmp al, 'H'
je cmd_h
cmp al, 'R' cmp al, 'R'
je cmd_r je cmd_r
cmp al, 'T' cmp al, 'T'
@ -154,74 +74,13 @@ cerr: mov al, '?'
call putc call putc
jmp crlf jmp crlf
cmd_?: mov si, .txt %include "debug/chario.asm"
jmp putcs %include "debug/parse.asm"
.txt: db "G Go", 0x0A, 0x0D %include "debug/names.asm"
db "R[r] Print register values", 0x0A, 0x0D
db "T Single-Step", 0x0A, 0x0D
db 0
cmd_g: and word [reg_fl+1], 0xfe %include "debug/edit.asm"
jmp return %include "debug/run.asm"
%include "debug/util.asm"
cmd_r: cmp byte [si], 0
je printregs
call eat_register
jc .err
mov al, [cs:bx+rnames]
call putc
mov al, [cs:bx+rnames+1]
call putc
call space
call edit_word
call crlf
ret
.err: mov di, eat_register.emsg
jmp parse_error
cmd_t: or word [reg_fl+1], 0x03
jmp return
printregs:
mov cx, 13
xor bx, bx
mov ah, 0x0e
mov si, reg_ax
.loop: push cx
mov dx, [cs:si+rnames]
lodsw
call printreg
pop cx
loop .loop
mov dx, [reg_fl]
mov si, fnames
mov cx, 16
.floop: mov al, [cs:si]
inc si
cmp al, '+'
je .fskip
test dx, 0x8000
jnz .fprnt
mov al, '-'
.fprnt: int 0x10
.fskip: shl dx, 1
loop .floop
call crlf
ret
printreg:
push ax
mov al, dl
call putc
mov al, dh
call putc
mov al, '='
call putc
pop dx
call print16
call space
ret
align 512 align 512