BIBOOT.ASM

; [ This translation created 10-Feb-83 by Version 4.3 ]

	.RADIX  8		; To be safe

CSEG	SEGMENT PUBLIC 'CODESG' 
	ASSUME  CS:CSEG

INCLUDE	OEM.H

	TITLE   BIBOOT - Initialization File for ASM86 BASICs
COMMENT	*

--------- --- ---- -- --------- -----------
COPYRIGHT (C) 1982 BY MICROSOFT CORPORATION
--------- --- ---- -- --------- -----------

        by Niklas Traub
        *
	INCLUDE	GIO86U
	.SALL

CPM86=0

	INCLUDE	MSDOSU

	PAGE	
	SUBTTL  ASM86 Version
;
;  There is a problem with running the ASM86 sources for BASIC as they
; stand.  MSDOS puts a 100 hex byte control block at the beginning of the
; EXE file and sets up the ES register to point to it.  BASIC, however,
; expects this block to be at 0 in the code segment. The quick and dirty
; solution is to copy the block into the code segment before doing anything
; else.  This module is included in the linker file list AFTER all others,
; but is executed first since it is defined as the entry point.
;  A 100H bytes are copied from ES:0 to CS:0 and then jump is done to
; the START label.  To accomodate the block, BINTRP should have an ORG 100H
; before any code.
;
; NOTE: Never convert the EXE file to a COM file.  COM files have the CS
;       register pointing to the control block on entry, so all offsets
;       for immediate values will be off by 100H.
;
	EXTRN	START:NEAR

;BIBOOT - ASM86 Version Specific Initialization
;Entry  - ES:0 pointing to start of control block.
;         DS:0 pointing to start of control block.
;
BIBOOT:
	MOV	CX,CS		; Get BASIC's segment
	MOV	ES,CX		; Make it the destination segment
	XOR	SI,SI		; Start at ES:0
	XOR	DI,DI		; Destination is CS:0
	MOV	CX,200O		; There are 100H bytes to move
	CLD	
 REP	MOVSW
	MOV	CX,DS		; Restore segment registers
	MOV	ES,CX
	JMP	START
CSEG    ENDS
;
; Last label in data segment.  Is used by BASIC to initialize TXTTAB, etc.
;
DSEG    SEGMENT PUBLIC 'DATASG'
        ASSUME  DS:DSEG
        PUBLIC  LSTVAR
LSTVAR  LABEL   WORD
DSEG    ENDS
CSEG    SEGMENT PUBLIC 'CODESG'
        ASSUME  CS:CSEG
CSEG	ENDS
	END	BIBOOT		; BIBOOT is the entry point.
;