Everyone, say hello to a real floating point emulator!

The fpemul written for Linux by W. Metzenthen: ported to NetBSD and
then to FreeBSD, and now back to OpenBSD.

1 files changed, 189 insertions, 0 deletions

diff --git a/sys/gnu/arch/i386/fpemul/fpu_emu.h b/sys/gnu/arch/i386/fpemul/fpu_emu.h
new file mode 100644
index 00000000000..e6e0890a99d
--- /dev/null
+++ b/sys/gnu/arch/i386/fpemul/fpu_emu.h
@@ -0,0 +1,189 @@
+/*	$OpenBSD: fpu_emu.h,v 1.1 1996/08/27 10:32:46 downsj Exp $	*/
+/*
+ *  fpu_emu.h
+ *
+ *
+ * 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.
+ *
+ *
+ *     $FreeBSD: fpu_emu.h,v 1.3 1994/06/10 07:44:19 rich Exp $
+ *
+ */
+
+
+#ifndef _FPU_EMU_H_
+#define _FPU_EMU_H_
+
+/*
+ * Define DENORM_OPERAND to make the emulator detect denormals
+ * and use the denormal flag of the status word. Note: this only
+ * affects the flag and corresponding interrupt, the emulator
+ * will always generate denormals and operate upon them as required.
+ */
+#define DENORM_OPERAND
+
+/*
+ * Define PECULIAR_486 to get a closer approximation to 80486 behaviour,
+ * rather than behaviour which appears to be cleaner.
+ * This is a matter of opinion: for all I know, the 80486 may simply
+ * be complying with the IEEE spec. Maybe one day I'll get to see the
+ * spec...
+ */
+#define PECULIAR_486
+
+#ifdef _LOCORE
+#include <gnu/arch/i386/fpemul/fpu_asm.h>
+#define	Const(x)	$/**/x
+#else
+#define	Const(x)	x
+#endif
+
+#define EXP_BIAS	Const(0)
+#define EXP_OVER	Const(0x4000)	/* smallest invalid large exponent */
+#define	EXP_UNDER	Const(-0x3fff)	/* largest invalid small exponent */
+
+#define SIGN_POS	Const(0)
+#define SIGN_NEG	Const(1)
+
+/* Keep the order TW_Valid, TW_Zero, TW_Denormal */
+#define TW_Valid	Const(0)/* valid */
+#define TW_Zero		Const(1)/* zero */
+/* The following fold to 2 (Special) in the Tag Word */
+#define TW_Denormal     Const(4)/* De-normal */
+#define TW_Infinity	Const(5)/* + or - infinity */
+#define	TW_NaN		Const(6)/* Not a Number */
+
+#define TW_Empty	Const(7)/* empty */
+
+ /* #define TW_FPU_Interrupt Const(0x80) *//* Signals an interrupt */
+
+
+#ifndef _LOCORE
+
+#include <sys/types.h>
+#include <gnu/arch/i386/fpemul/math_emu.h>
+
+#ifdef PARANOID
+extern char emulating;
+#define REENTRANT_CHECK(state) emulating = (state)
+#define ON 1
+#define OFF 0
+#else
+#define REENTRANT_CHECK(state)
+#endif				/* PARANOID */
+
+typedef void (*FUNC) (void);
+typedef struct fpu_reg FPU_REG;
+
+#define	st(x)	( regs[((top+x) &7 )] )
+
+#define	STACK_OVERFLOW	(st_new_ptr = &st(-1), st_new_ptr->tag != TW_Empty)
+#define	NOT_EMPTY(i)	(st(i).tag != TW_Empty)
+#define	NOT_EMPTY_0	(FPU_st0_tag ^ TW_Empty)
+
+extern unsigned char FPU_rm;
+
+extern char FPU_st0_tag;
+extern FPU_REG *FPU_st0_ptr;
+
+extern void *FPU_data_address;
+
+extern FPU_REG FPU_loaded_data;
+
+#define pop()	{ FPU_st0_ptr->tag = TW_Empty; top++; }
+
+/* push() does not affect the tags */
+#define push()	{ top--; FPU_st0_ptr = st_new_ptr; }
+
+
+#define reg_move(x, y) { \
+		 *(short *)&((y)->sign) = *(short *)&((x)->sign); \
+		 *(long *)&((y)->exp) = *(long *)&((x)->exp); \
+		 *(long long *)&((y)->sigl) = *(long long *)&((x)->sigl); }
+
+
+/*----- Prototypes for functions written in assembler -----*/
+/* extern void reg_move(FPU_REG *a, FPU_REG *b); */
+
+extern void mul64(long long *a, long long *b, long long *result);
+extern void poly_div2(long long *x);
+extern void poly_div4(long long *x);
+extern void poly_div16(long long *x);
+extern void
+polynomial(unsigned accum[], unsigned x[],
+    unsigned short terms[][4], int n);
+	extern void normalize(FPU_REG * x);
+	extern void normalize_nuo(FPU_REG * x);
+	extern void reg_div(FPU_REG * arg1, FPU_REG * arg2, FPU_REG * answ,
+            unsigned int control_w);
+	extern void reg_u_sub(FPU_REG * arg1, FPU_REG * arg2, FPU_REG * answ,
+            unsigned int control_w);
+	extern void reg_u_mul(FPU_REG * arg1, FPU_REG * arg2, FPU_REG * answ,
+            unsigned int control_w);
+	extern void reg_u_div(FPU_REG * arg1, FPU_REG * arg2, FPU_REG * answ,
+            unsigned int control_w);
+	extern void reg_u_add(FPU_REG * arg1, FPU_REG * arg2, FPU_REG * answ,
+            unsigned int control_w);
+	extern void wm_sqrt(FPU_REG * n, unsigned int control_w);
+	extern unsigned shrx(void *l, unsigned x);
+	extern unsigned shrxs(void *v, unsigned x);
+	extern unsigned long div_small(unsigned long long *x, unsigned long y);
+	extern void round_reg(FPU_REG * arg, unsigned int extent,
+            unsigned int control_w);
+
+#ifndef MAKING_PROTO
+#include <gnu/arch/i386/fpemul/fpu_proto.h>
+#endif
+
+#endif				/* _LOCORE */
+
+#endif				/* _FPU_EMU_H_ */