Category : HD Utilities
Archive   : WDFMT250.ZIP
Filename : AT_IO.ASM

; this file has some fast asmbly routines in it
; the routines use the C calling method for a small model
;
;

.286c ; 80286 AT code
DOSSEG ; use dos segments
.MODEL LARGE
.CODE

; _WR_BLOCK WILL WRITE ONE 512 BLOCK OF DATA EVERY TIME A DRQ IS THERE
; INPUT : [BP+4] POINTER TO START OF BUFFER
; OUTPUT: NONE



PUBLIC _WR_BLOCK
_WR_BLOCK PROC FAR
ENTER 2,0
PUSHA
PUSH DS

MOV BX,[BP+6] ; POINTER TO BUFFER offset
MOV AX,[BP+8] ;POINTER SEGMENT
MOV DS,AX
MOV DX,1F7H ;COMMAND REG
MOV AL,30H
OUT DX,AL ;SEND WRITE COMMAND

wrb_10: NOP ;DELAY
JMP SHORT $+2
NOP ;DELAY
JMP SHORT $+2
NOP ;DELAY
JMP SHORT $+2
NOP ;DELAY
JMP SHORT $+2
NOP ;DELAY
JMP SHORT $+2
NOP ;DELAY
JMP SHORT $+2
NOP ;DELAY

BUSY_LP:
IN AL,DX ;GET STATUS
JMP SHORT $+2
NOP
AND AL,80H ;MASK ALL BUT BUSY
JNZ BUSY_LP

IN AL,DX ;CHECK FOR DRQ
AND AL,8
JZ ALL_DONE ;SKIP, IF NO DRQ

MOV DX,01F0H ;DATA BUFFER PORT
MOV CX,256 ;1 SECTOR
CLD

MOV SI,BX ;SERVICE CONTROLLER BUFFER
REP OUTSW ;ELSE, WRITE COMMAND
MOV DX,1F7H ;POINT TO STATUS REG
JMP wrb_10


ALL_DONE:
IN AL,DX ;CHECK FOR ERROR
AND AL,05H ; CHECK FOR ERROR OR ECC
JNZ DISK_ERR ;JMP, IF ERROR

CLC
POP DS
POPA
LEAVE
RET

DISK_ERR:
STC
POP DS
POPA
LEAVE
RET
_WR_BLOCK ENDP



END