Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 183 insertions, 0 deletions

diff --git a/arch/x86/math-emu/reg_divide.c b/arch/x86/math-emu/reg_divide.c
new file mode 100644
index 000000000..08c2f6de0
--- /dev/null
+++ b/arch/x86/math-emu/reg_divide.c
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0
+/*---------------------------------------------------------------------------+
+ |  reg_divide.c                                                             |
+ |                                                                           |
+ | Divide one FPU_REG by another and put the result in a destination FPU_REG.|
+ |                                                                           |
+ | Copyright (C) 1996                                                        |
+ |                  W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
+ |                  E-mail   billm@jacobi.maths.monash.edu.au                |
+ |                                                                           |
+ |    Return value is the tag of the answer, or-ed with FPU_Exception if     |
+ |    one was raised, or -1 on internal error.                               |
+ |                                                                           |
+ +---------------------------------------------------------------------------*/
+
+/*---------------------------------------------------------------------------+
+ | The destination may be any FPU_REG, including one of the source FPU_REGs. |
+ +---------------------------------------------------------------------------*/
+
+#include "exception.h"
+#include "reg_constant.h"
+#include "fpu_emu.h"
+#include "fpu_system.h"
+
+/*
+  Divide one register by another and put the result into a third register.
+  */
+int FPU_div(int flags, int rm, int control_w)
+{
+	FPU_REG x, y;
+	FPU_REG const *a, *b, *st0_ptr, *st_ptr;
+	FPU_REG *dest;
+	u_char taga, tagb, signa, signb, sign, saved_sign;
+	int tag, deststnr;
+
+	if (flags & DEST_RM)
+		deststnr = rm;
+	else
+		deststnr = 0;
+
+	if (flags & REV) {
+		b = &st(0);
+		st0_ptr = b;
+		tagb = FPU_gettag0();
+		if (flags & LOADED) {
+			a = (FPU_REG *) rm;
+			taga = flags & 0x0f;
+		} else {
+			a = &st(rm);
+			st_ptr = a;
+			taga = FPU_gettagi(rm);
+		}
+	} else {
+		a = &st(0);
+		st0_ptr = a;
+		taga = FPU_gettag0();
+		if (flags & LOADED) {
+			b = (FPU_REG *) rm;
+			tagb = flags & 0x0f;
+		} else {
+			b = &st(rm);
+			st_ptr = b;
+			tagb = FPU_gettagi(rm);
+		}
+	}
+
+	signa = getsign(a);
+	signb = getsign(b);
+
+	sign = signa ^ signb;
+
+	dest = &st(deststnr);
+	saved_sign = getsign(dest);
+
+	if (!(taga | tagb)) {
+		/* Both regs Valid, this should be the most common case. */
+		reg_copy(a, &x);
+		reg_copy(b, &y);
+		setpositive(&x);
+		setpositive(&y);
+		tag = FPU_u_div(&x, &y, dest, control_w, sign);
+
+		if (tag < 0)
+			return tag;
+
+		FPU_settagi(deststnr, tag);
+		return tag;
+	}
+
+	if (taga == TAG_Special)
+		taga = FPU_Special(a);
+	if (tagb == TAG_Special)
+		tagb = FPU_Special(b);
+
+	if (((taga == TAG_Valid) && (tagb == TW_Denormal))
+	    || ((taga == TW_Denormal) && (tagb == TAG_Valid))
+	    || ((taga == TW_Denormal) && (tagb == TW_Denormal))) {
+		if (denormal_operand() < 0)
+			return FPU_Exception;
+
+		FPU_to_exp16(a, &x);
+		FPU_to_exp16(b, &y);
+		tag = FPU_u_div(&x, &y, dest, control_w, sign);
+		if (tag < 0)
+			return tag;
+
+		FPU_settagi(deststnr, tag);
+		return tag;
+	} else if ((taga <= TW_Denormal) && (tagb <= TW_Denormal)) {
+		if (tagb != TAG_Zero) {
+			/* Want to find Zero/Valid */
+			if (tagb == TW_Denormal) {
+				if (denormal_operand() < 0)
+					return FPU_Exception;
+			}
+
+			/* The result is zero. */
+			FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
+			setsign(dest, sign);
+			return TAG_Zero;
+		}
+		/* We have an exception condition, either 0/0 or Valid/Zero. */
+		if (taga == TAG_Zero) {
+			/* 0/0 */
+			return arith_invalid(deststnr);
+		}
+		/* Valid/Zero */
+		return FPU_divide_by_zero(deststnr, sign);
+	}
+	/* Must have infinities, NaNs, etc */
+	else if ((taga == TW_NaN) || (tagb == TW_NaN)) {
+		if (flags & LOADED)
+			return real_2op_NaN((FPU_REG *) rm, flags & 0x0f, 0,
+					    st0_ptr);
+
+		if (flags & DEST_RM) {
+			int tag;
+			tag = FPU_gettag0();
+			if (tag == TAG_Special)
+				tag = FPU_Special(st0_ptr);
+			return real_2op_NaN(st0_ptr, tag, rm,
+					    (flags & REV) ? st0_ptr : &st(rm));
+		} else {
+			int tag;
+			tag = FPU_gettagi(rm);
+			if (tag == TAG_Special)
+				tag = FPU_Special(&st(rm));
+			return real_2op_NaN(&st(rm), tag, 0,
+					    (flags & REV) ? st0_ptr : &st(rm));
+		}
+	} else if (taga == TW_Infinity) {
+		if (tagb == TW_Infinity) {
+			/* infinity/infinity */
+			return arith_invalid(deststnr);
+		} else {
+			/* tagb must be Valid or Zero */
+			if ((tagb == TW_Denormal) && (denormal_operand() < 0))
+				return FPU_Exception;
+
+			/* Infinity divided by Zero or Valid does
+			   not raise and exception, but returns Infinity */
+			FPU_copy_to_regi(a, TAG_Special, deststnr);
+			setsign(dest, sign);
+			return taga;
+		}
+	} else if (tagb == TW_Infinity) {
+		if ((taga == TW_Denormal) && (denormal_operand() < 0))
+			return FPU_Exception;
+
+		/* The result is zero. */
+		FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
+		setsign(dest, sign);
+		return TAG_Zero;
+	}
+#ifdef PARANOID
+	else {
+		EXCEPTION(EX_INTERNAL | 0x102);
+		return FPU_Exception;
+	}
+#endif /* PARANOID */
+
+	return 0;
+}