rdos/debug/chario.asm

138 lines
2.1 KiB
NASM

; Print AL
space: mov al, ' '
putc: push bx
xor bx, bx
mov ah, 0x0e
int 0x10
pop bx
ret
; Print code string CS:SI
putcs: push ds
push cs
pop ds
call putds
pop ds
ret
; Print data string DS:SI
putds: lodsb
test al, al
jz .ret
call putc
jmp putds
.ret: ret
crlf: mov al, 0x0A
call putc
mov al, 0x0D
jmp putc
print16:
mov cl, 4
; this double-call is essentially a 4 times repeating loop
call .c1
.c1: call .c2
.c2: ; grab highest nibble from dx
mov al, dh
; remove highest nibble from dx
shl dx, cl
; shift away second-highest nibble that we accidentally copied
shr al, cl
; map 0-9 to ascii codes for '0' to '9'
add al, 0x30
; if result is larger than '9', ...
cmp al, 0x3a
jl putc
; ... add 7 so we continue at 'A'
add al, 7
jmp putc
; Read character
getc: xor ax, ax
int 0x16
test al, al
jz getc
test al, 0x80
jnz getc
ret
; Read uppercased character
getcu: call getc
cmp al, 'a'
jc .ret
cmp al, 'z'
ja .ret
and al, 0xDF
.ret: ret
; Read hexadecimal character
getch: call getcu
; everything above F is invalid
cmp al, 'F'
ja getch
; everything above or equal A is ok
cmp al, 'A'
jae .ret
; everything above 9 is invalid
cmp al, '9'
ja getc
; everything above or equal 0 is valid
cmp al, '0'
jae .ret
; everything above or equal ' ' is invalid
cmp al, ' '
jae getch
.ret: ret
; Read string into inbuf
; IN ingetc ptr to getc function
; inlen max number of chars
gets: push bx
mov di, inbuf
; calculate max pointer for writing
mov dx, [inmin]
.loop: call [ingetc]
; test for Ctrl+C, Enter and Backspace
cmp al, 0x03
je .can
cmp al, 0x0D
je .enter
cmp al, 0x08
je .bs
; ignore other ctl chars
cmp al, 0x20
jc .loop
; check if we are full
mov bx, di
sub bx, inbuf
; bl is now number of characters we have
cmp bl, dh
jnc .loop
stosb
call putc
jmp .loop
; backspace: print, print space, print backspace again
.bs: cmp di, inbuf
jbe .loop
push ax
call putc
call space
pop ax
call putc
dec di
jmp .loop
; ctrl+c: return with carry set
.can: stc
pop bx
ret
; enter: if enough chars, return
.enter: mov bx, di
sub bx, inbuf
cmp bl, dl
jc .loop
xor al, al
stosb
pop bx
ret