158 lines
5.5 KiB
C
158 lines
5.5 KiB
C
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static char *sccsid =
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"@(#) disfp.c, Ver. 2.1 created 00:00:00 87/09/01";
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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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* *
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* Copyright (C) 1987 G. M. Harding, all rights reserved *
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* *
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* Permission to copy and redistribute is hereby granted, *
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* provided full source code, with all copyright notices, *
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* accompanies any redistribution. *
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* *
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* This file contains handler routines for the numeric op- *
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* codes of the 8087 co-processor, as well as a few other *
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* opcodes which are related to 8087 emulation. *
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* *
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* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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#include "dis.h" /* Disassembler declarations */
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#define FPINT0 0xd8 /* Floating-point interrupts */
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#define FPINT1 0xd9
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#define FPINT2 0xda
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#define FPINT3 0xdb
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#define FPINT4 0xdc
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#define FPINT5 0xdd
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#define FPINT6 0xde
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#define FPINT7 0xdf
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/* Test for floating opcodes */
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#define ISFLOP(x) \
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(((x) >= FPINT0) && ((x) <= FPINT7))
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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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* *
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* This is the handler for the escape family of opcodes. *
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* These opcodes place the contents of a specified memory *
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* location on the system bus, for access by a peripheral *
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* or by a co-processor such as the 8087. (The 8087 NDP is *
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* accessed only via bus escapes.) Due to a bug in the *
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* PC/IX assembler, the "esc" mnemonic is not recognized; *
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* consequently, escape opcodes are disassembled as .byte *
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* directives, with the appropriate mnemonic and operand *
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* included as a comment. FOR NOW, those escape sequences *
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* corresponding to 8087 opcodes are treated as simple *
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* escapes. *
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* *
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* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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void
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eshand(j)
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register int j; /* Pointer to optab[] entry */
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{/* * * * * * * * * * START OF eshand() * * * * * * * * * */
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register char *a;
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register int k;
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objini(j);
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FETCH(k);
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a = mtrans((j & 0xfd),(k & 0xc7),TR_STD);
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mtrunc(a);
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printf("\t.byte\t0x%02.2x\t\t| esc\t%s\n",j,a);
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for (k = 1; k < objptr; ++k)
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printf("\t.byte\t0x%02.2x\n",objbuf[k]);
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}/* * * * * * * * * * * END OF eshand() * * * * * * * * * * */
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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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* *
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* This is the handler routine for floating-point opcodes. *
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* Since PC/IX must accommodate systems with and without *
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* 8087 co-processors, it allows floating-point operations *
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* to be initiated in either of two ways: by a software *
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* interrput whose type is in the range 0xd8 through 0xdf, *
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* or by a CPU escape sequence, which is invoked by an op- *
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* code in the same range. In either case, the subsequent *
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* byte determines the actual numeric operation to be per- *
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* formed. However, depending on the method of access, *
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* either one or two code bytes will precede that byte, *
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* and the fphand() routine has no way of knowing whether *
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* it was invoked by interrupt or by an escape sequence. *
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* Therefore, unlike all of the other handler routines ex- *
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* cept dfhand(), fphand() does not initialize the object *
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* buffer, leaving that chore to the caller. *
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* *
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* FOR NOW, fphand() does not disassemble floating-point *
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* opcodes to floating mnemonics, but simply outputs the *
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* object code as .byte directives. *
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* *
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* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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void
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fphand(j)
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register int j; /* Pointer to optab[] entry */
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{/* * * * * * * * * * START OF fphand() * * * * * * * * * */
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register int k;
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segflg = 0;
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FETCH(k);
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printf("\t.byte\t0x%02.2x\t\t| 8087 code sequence\n",
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objbuf[0]);
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for (k = 1; k < objptr; ++k)
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printf("\t.byte\t0x%02.2x\n",objbuf[k]);
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/* objout(); FOR NOW */
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}/* * * * * * * * * * * END OF fphand() * * * * * * * * * * */
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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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* *
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* This is the handler for variable software interrupt *
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* opcodes. It is included in this file because PC/IX im- *
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* plements its software floating-point emulation by means *
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* of interrupts. Any interrupt in the range 0xd8 through *
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* 0xdf is an NDP-emulation interrupt, and is specially *
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* handled by the assembler. *
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* *
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* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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void
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inhand(j)
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register int j; /* Pointer to optab[] entry */
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{/* * * * * * * * * * START OF inhand() * * * * * * * * * */
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register int k;
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objini(j);
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FETCH(k);
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if (ISFLOP(k))
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{
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fphand(k);
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return;
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}
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printf("%s\t%d\n",optab[j].text,k);
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objout();
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}/* * * * * * * * * * * END OF inhand() * * * * * * * * * * */
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