**************************************************************************** * * $RCSfile: OberonSysDIVMOD.asm $ * Description: Runtime support for the Oberon-A compiler * * Created by: fjc (Frank Copeland) * $Revision: 1.2 $ * $Author: fjc $ * $Date: 1994/05/12 20:31:15 $ * * Copyright © 1994, Frank Copeland. * This file is part of the Oberon-A Library. * See Oberon-A.doc for conditions of use and distribution. * * Log entries are at the end of the file. * **************************************************************************** * * This file contains the MC68000 source code for part of the runtime * support library of the Oberon-A compiler. It contains the code to * perform division and modulus operations on 32-bit signed integers * (LONGINTs). * * Other parts of the runtime system may be found in the other files in * this directory. The object files resulting from assembling these * files are concatenated to create OberonSys.lib. * * This code is by definition *not* re-entrant and is not suitable for * creating shared-code libraries. * * Acknowledgements * ---------------- * * The 32-bit multiply and divide procedures are from the runtime * library of Patrick Quaid's PCQ freeware Pascal compiler, which in * turn came from the runtime library of Sozobon C. * ********************************************************************** ;--------------------------------------------------------------------- ; Program unit hunk name TTL OberonSys ;--------------------------------------------------------------------- ; Imports INCLUDE "OberonSys.i" ********************************************************************** ********** * lmath.s ********** * Copyright (c) 1988 by Sozobon, Limited. Author: Johann Ruegg * * Permission is granted to anyone to use this software for any purpose * on any computer system, and to redistribute it freely, with the * following restrictions: * 1) No charge may be made other than reasonable charges for reproduction. * 2) Modified versions must be clearly marked as such. * 3) The authors are not responsible for any harmful consequences * of using this software, even if they result from defects in it. * * For PCQ Pascal: * These are the 32-bit math functions from Sozobon-C, * as noted above. I changed the names of the routines to * be more similar to the rest of my library, and handle the * divide by zero condition differently. Other than that I * haven't changed the code a bit. * For Oberon-A: * I have changed the names (again) and modified the * routines to accept parameters passed in registers instead of * on the stack, in keeping with the conventions I use in the * rest of the compiler. ********************************************************************** ;---------------------------------------------------------------- ; PROCEDURE OberonSys_DIV ; l1 {D0} : LONGINT; ; l2 {D1} : LONGINT) ; : LONGINT; ; ; Calculates l1 DIV l2, returning the result in D0. ;---------------------------------------------------------------- SECTION OberonSys,CODE XDEF OberonSys_DIV OberonSys_DIV: movem.l d2-d5,-(a7) ; save registers tst.l d0 smi d4 bpl ld1 neg.l d0 ld1: tst.l d1 smi d5 bpl ld2 neg.l d1 ld2: bsr i_ldiv /* d0 = d0/d1, d1 = d0%d1 */ cmp.b d4,d5 beq ld3 neg.l d0 ld3: ; tst.b d4 ; beq ld4 ; neg.l d1 ;ld4: movem.l (a7)+,d2-d5 rts ;--------------------------------------------------------------------- ;---------------------------------------------------------------- ; PROCEDURE OberonSys_MOD ; l1 {D0} : LONGINT; ; l2 {D1} : LONGINT) ; : LONGINT; ; ; Calculates l1 MOD l2, returning the result in D0. ;---------------------------------------------------------------- SECTION OberonSys,CODE XDEF OberonSys_MOD OberonSys_MOD: ; movem.l d2-d5,-(a7) ; save registers movem.l d2-d4,-(a7) ; save registers tst.l d0 smi d4 bpl lmd1 neg.l d0 lmd1: ; tst.l d1 ; smi d5 ; bpl lmd2 ; neg.l d1 ;lmd2: bsr i_ldiv /* d0 = d0/d1, d1 = d0%d1 */ ; cmp.b d4,d5 ; beq lmd3 ; neg.l d0 ;lmd3: tst.b d4 beq lmd4 neg.l d1 lmd4: move.l d1,d0 ; movem.l (a7)+,d2-d5 movem.l (a7)+,d2-d4 rts ;--------------------------------------------------------------------- SECTION OberonSys,CODE XREF OberonSys_CLEANUP *A in d0, B in d1, return A/B in d0, A%B in d1 i_ldiv: tst.l d1 bne.s nz1 * divide by zero moveq.l #OS_ZeroDiv,D0 ; HALT (ZeroDiv) bra OberonSys_CLEANUP nz1: cmp.l d1,d0 bhi norm beq is1 * AB and B is not 0 norm: cmp.l #1,d1 bne.s not1 * B==1, so ret A, rem 0 clr.l d1 rts * check for A short (implies B short also) not1: cmp.l #$ffff,d0 bhi slow * A short and B short -- use 'divu' divu d1,d0 /* d0 = REM:ANS */ swap d0 /* d0 = ANS:REM */ clr.l d1 move.w d0,d1 /* d1 = REM */ clr.w d0 swap d0 rts * check for B short slow: cmp.l #$ffff,d1 bhi slower * A long and B short -- use special stuff from gnu move.l d0,d2 clr.w d2 swap d2 divu d1,d2 /* d2 = REM:ANS of Ahi/B */ clr.l d3 move.w d2,d3 /* d3 = Ahi/B */ swap d3 move.w d0,d2 /* d2 = REM << 16 + Alo */ divu d1,d2 /* d2 = REM:ANS of stuff/B */ move.l d2,d1 clr.w d1 swap d1 /* d1 = REM */ clr.l d0 move.w d2,d0 add.l d3,d0 /* d0 = ANS */ rts * A>B, B > 1 slower: move.l #1,d2 clr.l d3 moreadj: cmp.l d0,d1 bhi.s adj add.l d2,d2 add.l d1,d1 bpl moreadj * we shifted B until its >A or sign bit set * we shifted #1 (d2) along with it adj: cmp.l d0,d1 bhi.s ltuns or.l d2,d3 sub.l d1,d0 ltuns: lsr.l #1,d1 lsr.l #1,d2 bne adj * d3=answer, d0=rem move.l d0,d1 move.l d3,d0 rts ;--------------------------------------------------------------------- END ; OberonSys ********************************************************************** * * $Log: OberonSysDIVMOD.asm $ * Revision 1.2 1994/05/12 20:31:15 fjc * - Prepared for release * * Revision 1.1 1994/01/15 18:31:52 fjc * Start of revision control * * (12 Jan 1994) Modified to assemble with PhxAss instead of A68K * ( 9 Jul 1993) Changed return code to OS_ZeroDiv. * (29 May 1993) Split OberonSys.asm into several files to create * OberonSys.lib. * **********************************************************************