rdos/bios/8086.asm

217 lines
2.3 KiB
NASM
Raw Normal View History

2019-10-28 11:49:42 +01:00
ORG BIOS
2019-10-25 01:11:19 +02:00
CPU 8086
2019-10-27 19:59:42 +01:00
DISKCX: EQU 0x8
DISKDX: EQU 0xA
DISKBX: EQU 0xC
2019-10-25 01:11:19 +02:00
JMP NEAR BOOT
JMP NEAR WBOOT
JMP NEAR CONST
JMP NEAR CONIN
JMP NEAR CONOUT
JMP NEAR LIST
JMP NEAR PUNCH
JMP NEAR READER
JMP NEAR HOME
JMP NEAR SELDSK
JMP NEAR SETTRK
JMP NEAR SETSEC
JMP NEAR SETDMA
JMP NEAR READ
JMP NEAR WRITE
JMP NEAR LISTST
BOOT:
MOV AL, 0x86
CALL MSG
DB "BIOS", 0
2019-10-25 01:11:19 +02:00
WBOOT:
XOR CX, CX
2019-10-28 11:49:42 +01:00
JMP BDOS
2019-10-25 01:11:19 +02:00
RET
; CHAR I/O
CONST:
MOV AH, 1
INT 0x16
JZ .END
MOV AL, 0xFF
RET
.END:
XOR AL, AL
RET
CONIN:
XOR AX, AX
INT 0x16
TEST AL, AL
JZ CONIN
RET
MSG:
POP SI
.LOOP:
MOV DL, BYTE [SI]
INC SI
TEST DL, DL
JZ .END
CALL CONOUT
JMP .LOOP
.END:
MOV DL, 0x20
CALL CONOUT
CALL PRINTAL
MOV DL, 0x0A
CALL CONOUT
MOV DL, 0x0D
CALL CONOUT
PUSH SI
RET
PRINTAL:
PUSH AX
PUSH DX
AAM 16
MOV DL, AH
CALL PRINTNIB
MOV DL, AL
CALL PRINTNIB
POP DX
POP AX
RET
PRINTNIB:
ADD DL, 0x30
CMP DL, 0x3a
JL CONOUT
ADD DL, 0x07
2019-10-25 01:11:19 +02:00
CONOUT:
PUSH AX
PUSH BX
MOV AH, 0x0E
MOV AL, DL
XOR BX, BX
INT 0x10
POP BX
POP AX
RET
LIST:
PUSH DX
XOR AH, AH
MOV AL, DL
INT 0x17
POP DX
RET
LISTST:
STC
RET
PUNCH:
STC
RET
READER:
STC
RET
; DISK I/O
HOME:
RET
SELDSK:
MOV BYTE [DISKDX], CL
2019-10-25 01:11:19 +02:00
XOR BX, BX
RET
SETTRK:
PUSH CX
PUSH DX
MOV DX, CX
; CH for headnum, CL for SAL
MOV CX, 0x0006
; Take off LSB as head number
XOR CH, CH
RCR DX, 1
RCL CH, 1
MOV BYTE [DISKDX+1], CH
2019-10-25 01:11:19 +02:00
; DX is sector number now
; Shift into format for int13
; DX ------9876543210
SAL DX, CL
; DX 9876543210------
ROL DX, 1
ROL DX, 1
; DX 76543210------98
SAL DL, CL
; DX 7654321098------
AND WORD [DISKCX], 0x003F
OR WORD [DISKCX], DX
POP DX
POP CX
RET
SETSEC:
AND WORD [DISKCX], 0xFFA0
OR BYTE [DISKCX], CL
2019-10-25 01:11:19 +02:00
RET
SETDMA:
MOV WORD [DISKBX], CX
RET
READ:
PUSH CX
PUSH DX
PUSH BX
MOV AX, 0x0201
MOV CX, [DISKCX]
MOV DX, [DISKDX]
MOV BX, [DISKBX]
INT 0x13
XCHG AH, AL
POP BX
POP DX
POP CX
JC DISKERR
2019-10-25 01:11:19 +02:00
RET
WRITE:
PUSH CX
PUSH DX
PUSH BX
MOV AX, 0x0301
MOV CX, [DISKCX]
MOV DX, [DISKDX]
MOV BX, [DISKBX]
INT 0x13
XCHG AH, AL
POP BX
POP DX
POP CX
JC DISKERR
2019-10-25 01:11:19 +02:00
RET
DISKERR:
PUSHF
PUSH SI
CALL MSG
DB "DISKERR", 0
POP SI
POPF
2019-10-25 01:11:19 +02:00
RET