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+/*
+ * fpu_etc.c
+ *
+ * Implement a few FPU instructions.
+ *
+ *
+ * Copyright (C) 1992,1993,1994
+ * W. Metzenthen, 22 Parker St, Ormond, Vic 3163,
+ * Australia. E-mail billm@vaxc.cc.monash.edu.au
+ * All rights reserved.
+ *
+ * This copyright notice covers the redistribution and use of the
+ * FPU emulator developed by W. Metzenthen. It covers only its use
+ * in the 386BSD, FreeBSD and NetBSD operating systems. Any other
+ * use is not permitted under this copyright.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must include information specifying
+ * that source code for the emulator is freely available and include
+ * either:
+ * a) an offer to provide the source code for a nominal distribution
+ * fee, or
+ * b) list at least two alternative methods whereby the source
+ * can be obtained, e.g. a publically accessible bulletin board
+ * and an anonymous ftp site from which the software can be
+ * downloaded.
+ * 3. All advertising materials specifically mentioning features or use of
+ * this emulator must acknowledge that it was developed by W. Metzenthen.
+ * 4. The name of W. Metzenthen may not be used to endorse or promote
+ * products derived from this software without specific prior written
+ * permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+ * W. METZENTHEN BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *
+ * The purpose of this copyright, based upon the Berkeley copyright, is to
+ * ensure that the covered software remains freely available to everyone.
+ *
+ * The software (with necessary differences) is also available, but under
+ * the terms of the GNU copyleft, for the Linux operating system and for
+ * the djgpp ms-dos extender.
+ *
+ * W. Metzenthen June 1994.
+ *
+ *
+ * $Id: fpu_etc.c,v 1.3 1994/06/10 07:44:24 rich Exp $
+ *
+ */
+
+#include "param.h"
+#include "proc.h"
+#include "machine/cpu.h"
+#include "machine/pcb.h"
+
+#include "fpu_emu.h"
+#include "fpu_system.h"
+#include "exception.h"
+#include "status_w.h"
+#include "reg_constant.h"
+
+
+static void
+fchs(void)
+{
+ if (NOT_EMPTY_0) {
+ FPU_st0_ptr->sign ^= SIGN_POS ^ SIGN_NEG;
+ status_word &= ~SW_C1;
+ } else
+ stack_underflow();
+}
+
+static void
+fabs(void)
+{
+ if (FPU_st0_tag ^ TW_Empty) {
+ FPU_st0_ptr->sign = SIGN_POS;
+ status_word &= ~SW_C1;
+ } else
+ stack_underflow();
+}
+
+
+static void
+ftst_(void)
+{
+ switch (FPU_st0_tag) {
+ case TW_Zero:
+ setcc(SW_C3);
+ break;
+ case TW_Valid:
+
+#ifdef DENORM_OPERAND
+ if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
+ return;
+#endif /* DENORM_OPERAND */
+
+ if (FPU_st0_ptr->sign == SIGN_POS)
+ setcc(0);
+ else
+ setcc(SW_C0);
+ break;
+ case TW_NaN:
+ setcc(SW_C0 | SW_C2 | SW_C3); /* Operand is not comparable */
+ EXCEPTION(EX_Invalid);
+ break;
+ case TW_Infinity:
+ if (FPU_st0_ptr->sign == SIGN_POS)
+ setcc(0);
+ else
+ setcc(SW_C0);
+ EXCEPTION(EX_Invalid);
+ break;
+ case TW_Empty:
+ setcc(SW_C0 | SW_C2 | SW_C3);
+ EXCEPTION(EX_StackUnder);
+ break;
+ default:
+ setcc(SW_C0 | SW_C2 | SW_C3); /* Operand is not comparable */
+ EXCEPTION(EX_INTERNAL | 0x14);
+ break;
+ }
+}
+
+static void
+fxam(void)
+{
+ int c = 0;
+ switch (FPU_st0_tag) {
+ case TW_Empty:
+ c = SW_C3 | SW_C0;
+ break;
+ case TW_Zero:
+ c = SW_C3;
+ break;
+ case TW_Valid:
+ /* This will need to be changed if TW_Denormal is ever used. */
+ if (FPU_st0_ptr->exp <= EXP_UNDER)
+ c = SW_C2 | SW_C3; /* Denormal */
+ else
+ c = SW_C3;
+ break;
+ case TW_NaN:
+ c = SW_C0;
+ break;
+ case TW_Infinity:
+ c = SW_C2 | SW_C0;
+ break;
+ }
+ if (FPU_st0_ptr->sign == SIGN_NEG)
+ c |= SW_C1;
+ setcc(c);
+}
+
+static FUNC fp_etc_table[] = {
+ fchs, fabs, Un_impl, Un_impl, ftst_, fxam, Un_impl, Un_impl
+};
+
+void
+fp_etc()
+{
+ (fp_etc_table[FPU_rm]) ();
+}