163 lines
4.1 KiB
C
163 lines
4.1 KiB
C
/*
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* fpu_etc.c
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*
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* Implement a few FPU instructions.
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*
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*
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* Copyright (C) 1992, 1993 W. Metzenthen, 22 Parker St, Ormond,
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* Vic 3163, Australia.
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* E-mail apm233m@vaxc.cc.monash.edu.au
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* All rights reserved.
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*
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* This copyright notice covers the redistribution and use of the
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* FPU emulator developed by W. Metzenthen. It covers only its use
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* in the 386BSD operating system. Any other use is not permitted
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* under this copyright.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must include information specifying
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* that source code for the emulator is freely available and include
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* either:
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* a) an offer to provide the source code for a nominal distribution
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* fee, or
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* b) list at least two alternative methods whereby the source
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* can be obtained, e.g. a publically accessible bulletin board
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* and an anonymous ftp site from which the software can be
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* downloaded.
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* 3. All advertising materials specifically mentioning features or use of
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* this emulator must acknowledge that it was developed by W. Metzenthen.
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* 4. The name of W. Metzenthen may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* W. METZENTHEN BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include "param.h"
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#include "proc.h"
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#include "machine/cpu.h"
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#include "machine/pcb.h"
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#include "fpu_emu.h"
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#include "fpu_system.h"
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#include "exception.h"
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#include "status_w.h"
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#include "reg_constant.h"
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static void
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fchs(void)
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{
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if (NOT_EMPTY_0) {
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FPU_st0_ptr->sign ^= SIGN_POS ^ SIGN_NEG;
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status_word &= ~SW_C1;
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} else
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stack_underflow();
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}
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static void
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fabs(void)
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{
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if (FPU_st0_tag ^ TW_Empty) {
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FPU_st0_ptr->sign = SIGN_POS;
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status_word &= ~SW_C1;
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} else
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stack_underflow();
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}
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static void
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ftst_(void)
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{
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switch (FPU_st0_tag) {
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case TW_Zero:
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setcc(SW_C3);
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break;
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case TW_Valid:
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#ifdef DENORM_OPERAND
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if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
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return;
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#endif /* DENORM_OPERAND */
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if (FPU_st0_ptr->sign == SIGN_POS)
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setcc(0);
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else
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setcc(SW_C0);
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break;
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case TW_NaN:
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setcc(SW_C0 | SW_C2 | SW_C3); /* Operand is not comparable */
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EXCEPTION(EX_Invalid);
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break;
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case TW_Infinity:
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if (FPU_st0_ptr->sign == SIGN_POS)
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setcc(0);
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else
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setcc(SW_C0);
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EXCEPTION(EX_Invalid);
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break;
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case TW_Empty:
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setcc(SW_C0 | SW_C2 | SW_C3);
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EXCEPTION(EX_StackUnder);
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break;
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default:
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setcc(SW_C0 | SW_C2 | SW_C3); /* Operand is not comparable */
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EXCEPTION(EX_INTERNAL | 0x14);
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break;
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}
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}
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static void
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fxam(void)
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{
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int c = 0;
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switch (FPU_st0_tag) {
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case TW_Empty:
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c = SW_C3 | SW_C0;
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break;
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case TW_Zero:
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c = SW_C3;
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break;
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case TW_Valid:
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/* This will need to be changed if TW_Denormal is ever used. */
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if (FPU_st0_ptr->exp <= EXP_UNDER)
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c = SW_C2 | SW_C3; /* Denormal */
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else
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c = SW_C3;
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break;
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case TW_NaN:
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c = SW_C0;
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break;
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case TW_Infinity:
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c = SW_C2 | SW_C0;
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break;
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}
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if (FPU_st0_ptr->sign == SIGN_NEG)
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c |= SW_C1;
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setcc(c);
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}
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static FUNC fp_etc_table[] = {
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fchs, fabs, Un_impl, Un_impl, ftst_, fxam, Un_impl, Un_impl
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};
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void
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fp_etc()
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{
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(fp_etc_table[FPU_rm]) ();
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}
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