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174 lines
6.0 KiB
Plaintext
174 lines
6.0 KiB
Plaintext
;
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; File: FP020EQUS.a
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;
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; Contains: xxx put contents here xxx
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;
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; Written by: xxx put writers here xxx
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;
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; Copyright: © 1990 by Apple Computer, Inc., all rights reserved.
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;
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; Change History (most recent first):
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;
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; <2> 4/14/90 JJ Made changes to support new binary-to-decimal, 96-bit precision,
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; and improved Pack 5.
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; <1> 3/2/90 JJ First checked in.
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;
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; To Do:
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;
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;-----------------------------------------------------------
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; File: FPEQUS.a
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;-----------------------------------------------------------
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;-----------------------------------------------------------
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; 04JUL82: WRITTEN BY JEROME COONEN
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; Copyright Apple Computer, Inc., 1983,1984,1985,1989,1990
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; All Rights Reserved
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; 10AUG82: REMOVE OPWORD ERROR MASKS AND SET UP OPWORD
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; TESTS ON WORD, RATHER THAN LONG, BOUNDARY. (JTC)
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; 28AUG82: REMOVE FLAGS FOR STATE AREA ACCESS. (JTC)
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; 30AUG82: UNDERFLOW AND DIVBYZERO FLAGS SWAPPED (JTC)
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; 01SEP82: RND ENCODINGS CHANGED (JTC)
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; 03SEP82: FLAG ORDER REVERSED (JTC)
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; 13OCT82: ADD ROUND UP BIT (JTC)
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; 12DEC82: REMOVE PROJECTIVE MODE MATERIAL (JTC)
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; 13APR83: EXPAND COMMENT ABOUT STKREM... (JTC)
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; 29APR83: ADD OPHIBIT CONSTANT FOR DISTINGUISHING CLASS AND
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; COMPARE IN NANHANDLER. ADD NEXT CONSTANTS. (JTC)
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; 09MAY83: REPLACE STACK CONSTANTS WITH LINK CONSTANTS (JTC)
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; 26AUG83: MOVED FOR... EQUS FROM FPDRIVER TO HERE (JTC)
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; 01NOV83: PRECISION CONTROL TO MODE BITS (JTC)
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; 15APR84: MOVED FOR... EQUS BACK OUT TO FPDRIVER FROM HERE (JTC&DGH)
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; 26MAR85: ADDED QNANBIT=30 FOR CHANGE OF QUIET/SIGNAL NAN SENSE (JTC)
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; 24JAN90: MODIFICATIONS FOR 68020 SOFTWARE SANE (JPO)
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;
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; SOME BITS ARE ACCESSIBLE BY <TST; BMI> SEQUENCES BECAUSE
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; THEY OCCUR AT THE HIGH END OF A BYTE, WORD, OR LONG
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; SUBPIECE. WHENEVER SUCH TESTS ARE EXPLOITED (PREFERABLE
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; TO BTST), THE BIT NUMBER IS USED IN THE COMMENT.
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;-----------------------------------------------------------
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;-----------------------------------------------------------
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; STACK FRAME INFORMATION. AFTER ENTRY DO A "LINK A6,#-2"
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; TO GET STACK:
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; CNT WORD < OLD A6 < RET < OP < ADR1 < ADR2...
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; WITH A6 POINTING TO OLD A6. THEN THE FOLLOWING LINK
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; OFFSETS ACCESS STACK ELEMENTS.
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;-----------------------------------------------------------
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LKCNT EQU -2 ; BYTE COUNT FOR TRAP
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LKA6 EQU 0 ; SAVED A6
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LKRET EQU 4 ; RETURN ADDRESS
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LKOP EQU 8 ; OPWORD
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LKADR1 EQU 10 ; FIRST ADDRESS
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LKADR2 EQU 14 ; SECOND ADDRESS
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LKADR3 EQU 18 ; THIRD ADDRESS
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;-----------------------------------------------------------
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; WHEN A HALT EXIT IS TAKEN, THE STACK CONSISTS OF:
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; RET TO FP020 < OP < ADR1 < ADR2 < ADR3 < PTR
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; WHERE PTR REFERS TO THE THREE WORD STRUCTURE: CCR | D0
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; TO BE STUFFED AFTER RETURN TO PACKAGE.
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; TO RETURN TO EXECUTING PROGRAM JUST DO
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; MOVEA.L (SP)+,A0 ; RETURN ADRS
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; ADDA.W #18,SP ; KILL OP, 4 ADRS'S
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; JMP (A0)
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;-----------------------------------------------------------
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STKREM1 EQU 12 ; BYTES TO TOSS IF 1
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STKREM2 EQU 16 ; BYTES TO TOSS IF 2
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STKREM3 EQU 20 ; BYTES TO TOSS IF 3
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;-----------------------------------------------------------
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; POSITION OF ERROR BITS IN BYTE. W-MASKS ARE FOR SETTING
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; MULTIPLE EXCEPTIONS IN BITS $1F00 OF A WORD.
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;-----------------------------------------------------------
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ERRX EQU 4 ; INEXACT
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ERRZ EQU 3 ; DIVISION BY ZERO
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ERRO EQU 2 ; OVERFLOW
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ERRU EQU 1 ; UNDERFLOW
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ERRI EQU 0 ; INVALID
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ERRWXO EQU $1400 ; INEXACT AND OVERFLOW
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ERRWXU EQU $1200 ; INEXACT AND UNDERFLOW
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;-----------------------------------------------------------
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; RESULTS OF COMPARISONS, BASED ON CPU MAP: XNZVC.
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;-----------------------------------------------------------
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CMPE EQU $04 ; EQUAL
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CMPL EQU $19 ; LESS
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CMPG EQU $00 ; GREATER
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CMPU EQU $02 ; UNORDERED
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;-----------------------------------------------------------
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; CLASS OPERATOR RETURN CODES
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;-----------------------------------------------------------
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CLSNAN EQU 1 ; SIGNALING NAN
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CLQNAN EQU 2 ; QUIET NAN
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CLINF EQU 3 ; INFINITY
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CLZERO EQU 4 ; ZERO
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CLNORM EQU 5 ; NORMAL NUMBER
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CLDENORM EQU 6 ; DENORMAL NUMBER
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;-----------------------------------------------------------
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; OPWORD BITS, BASED ON WORD VALUE.
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;-----------------------------------------------------------
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TWOADRS EQU 00 ; 1 IFF 2 ADDRESSES
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OPHIBIT EQU 04 ; 0010 = OPCODE LEAD BIT
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DSTOUT EQU 05 ; 1 IFF NOT COMPARISON
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SRCIN EQU 06 ; 1 IFF SRC INPUT
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DSTIN EQU 07 ; 1 IFF DST INPUT
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DSTLO EQU 08 ; LO BIT OF DST FORMAT
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DSTMD EQU 09 ; MED BIT OF DST FORMAT
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DSTINT EQU 10 ; 1 IFF INTEGER OUTPUT
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SRCLO EQU 11 ; LO BIT OF SRC FORMAT
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SRCMD EQU 12 ; MED BIT OF SRC FORMAT
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SRCHI EQU 13 ; HI BIT OF SRC FORMAT
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DPREC EQU 14 ; DOUBLE OPERATION
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SPREC EQU 15 ; SINGLE OPERATION (TST.L)
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FPX96 EQU 05 ; 96-BIT EXTENDED FORMAT (IN OPWORD
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; ON STACK)
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;-----------------------------------------------------------
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; TESTS FOR OPERATIONS, ALL AS WORD TESTS. AND SOME
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; USEFUL OPCODES FOR B<->D CONVERSIONS.
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;-----------------------------------------------------------
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OPIFCPX EQU 1 ; 1 IFF CMPX VS CMP
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OPIFTR EQU 1 ; 1 IFF TRUNC VS ROUND
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OPAMASK EQU $001E ; ISOLATE OPCODE BITS
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OPFOMASK EQU $3800 ; TO GET SRC FORMAT BITS
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OPADD EQU $0000 ; ADD OPCODE
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OPMUL EQU $0004 ; MULTIPLY OPCODE
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OPDIV EQU $0006 ; DIVIDE OPCODE
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OPCMP EQU $0008 ; COMPARE WITHOUT EXCEPTIONS
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OP2EXT EQU $000E ; CONVERT TO EXTENDED
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OPEXT2 EQU $0010 ; CONVERT FROM EXTENDED
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OPRINT EQU $0014 ; ROUND TO INTEGER
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OPCLASS EQU $001C ; CLASS
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;-----------------------------------------------------------
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; MODE BITS AND MASKS IN BYTE.
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;-----------------------------------------------------------
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RNDMSK EQU $60 ; AS THOUGH IN LOW WORD
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RNDUP EQU $20
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RNDDN EQU $40
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RND0 EQU $60
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RNDLO EQU 5
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RNDHI EQU 6 ; LEAD RND BIT
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DBRMSK EQU $8f ; KILL RND BITS AND INEXACT
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RNDINC EQU 7 ; IN LOW BYTE OF WORD
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PRECMSK EQU RNDMSK ; IN LOW BYTE OF WORD
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;-----------------------------------------------------------
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; CONSTANT TO TWEAK NAN BIT IN HIGH LONG WORD OF SIG FIELD <26MAR85>
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;-----------------------------------------------------------
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QNANBIT EQU 30 ; 1-QUIET 0-SIGNALING <26MAR85>
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;-----------------------------------------------------------
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; ADDRESS OF ENVIRONMENT WORD AND HALTVECTOR IN LOW MEMORY
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;-----------------------------------------------------------
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FPSTATE EQU $A4A
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FPHV EQU $A4C
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