$TITLE('Series-III i8087 Linkage Module, Small Model')
$NOMACRO
$PAGEWIDTH(132)

; Intel insite Reference: BG59
; File Name: BG59S.A86

		NAME	LINK87_SMALL

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;									      ;
; Series-III i8087 Linkage Module, Small Compilation Model		      ;
;									      ;
; Written By:								      ;
; Mike Silverstone							      ;
; Brunswick Defense							      ;
; 3333 Harbor Blvd.							      ;
; Costa Mesa, California  92626-1009					      ;
; Revised: 27 Apr 82							      ;
;									      ;
; This module links the interrupt of the i8087 Numeric Data Processor on an   ;
; iSBC-337 Multimodule Math Board installed on the Series-III RPB-86 board to ;
; the FORTRAN-86 and PASCAL-86 math exception handlers and the RUN program    ;
; default math exception handler.  ISIS-II RUN, V1.0 and V1.3, do not	      ;
; recognize the existance of an i8087 Numeric Data Processor in the	      ;
; Series-III Microcomputer Development System.				      ;
;									      ;
; It is assumed that an Intel iSBC-337 Multimodule Math Board has been	      ;
; installed on the Series-III RPB-86 Board in accordance with the 142887-001  ;
; iSBC-337 Multimodule Numeric Data Processor Hardware Reference Manual.  It  ;
; is also assumed that a wire has been connected between P2-1, the math	      ;
; interrupt output on the iSBC-337 Multimodule Math Board, and E74, the	      ;
; programmable interrupt controller interrupt 7 input on the RPB-86 Board.    ;
;									      ;
; Three separate parts are in this module:				      ;
;   1. The first part loads the math interrupt procedure entry point into     ;
;      the RPB-86 Board interrupt vector array.				      ;
;   2. The second part contains the math interrupt procedure.  It generates   ;
;      a software interrupt 16 which is the standard Intel Numeric Data       ;
;      Processor exception handler entry point.				      ;
;   3. The third part modifies the ISIS-II RUN program default PIC mask to    ;
;      acknowledge the presence of the math interrupt on the RPB-86 Board     ;
;      PIC interrupt 7 input.						      ;
;									      ;
; This procedure must be called at the beginning of the user program to link  ;
; the i8087 to the Series-III Microcomputer Development System before any     ;
; floating point operations occur.  The linkage of the LINK87 procedure to    ;
; the user program will set up the proper PIC mask, and link the math	      ;
; interrupt vector and the math interrupt procedure to the user program.      ;
;									      ;
; NOTE:									      ;
; This module is compatible with the PL/M-86 Small and Compact models of      ;
; compilation.  With suitable modification it will also be compatible with    ;
; the PL/M-86 Medium and Large models of compilation.			      ;
;									      ;
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; LITERAL DECLARATIONS

PIC_MASK_PORT	EQU	0C2H			; RPB-86 PIC MASK PORT
i8087_MASK	EQU	01111111B		; MATH INTERRUPT MASK

CGROUP		GROUP	i8087_LINK

INT_63_SEG	SEGMENT AT 0FH
		ORG	0CH
		DD	MATH_EXCEPTION		; MATH INTERRUPT VECTOR
INT_63_SEG	ENDS

i8087_LINK	SEGMENT PUBLIC 'CODE'
		ASSUME CS:CGROUP

MATH_EXCEPTION	PROC NEAR
		INT	16			; CONVERT INTERRUPT 63 TO INTERRUPT 16
		IRET
MATH_EXCEPTION	ENDP

PUBLIC		LINK87
LINK87		PROC NEAR
		IN	AL,PIC_MASK_PORT	; GET EXISTING PIC MASK
		AND	AL,i8087_MASK		; ACKOWLEDGE MATH INTERRUPT
		OUT	PIC_MASK_PORT,AL	; LOAD REVISED PIC MASK
		RET
LINK87		ENDP

i8087_LINK	ENDS

		END