patch-2.4.20 linux-2.4.20/arch/parisc/math-emu/sfrem.c

• Lines: 291
• Date: Thu Nov 28 15:53:10 2002
• Orig file: linux-2.4.19/arch/parisc/math-emu/sfrem.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/parisc/math-emu/sfrem.c linux-2.4.20/arch/parisc/math-emu/sfrem.c
@@ -0,0 +1,290 @@
+/*
+ * Linux/PA-RISC Project (http://www.parisc-linux.org/)
+ *
+ * Floating-point emulation code
+ *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
+ *
+ *    This program is free software; you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation; either version 2, or (at your option)
+ *    any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+/*
+ * BEGIN_DESC
+ *
+ *  File:
+ *	@(#)	pa/spmath/sfrem.c		$Revision: 1.1 $
+ *
+ *  Purpose:
+ *	Single Precision Floating-point Remainder
+ *
+ *  External Interfaces:
+ *	sgl_frem(srcptr1,srcptr2,dstptr,status)
+ *
+ *  Internal Interfaces:
+ *
+ *  Theory:
+ *	<<please update with a overview of the operation of this file>>
+ *
+ * END_DESC
+*/
+
+
+
+#include "float.h"
+#include "sgl_float.h"
+
+/*
+ *  Single Precision Floating-point Remainder
+ */
+
+int
+sgl_frem (sgl_floating_point * srcptr1, sgl_floating_point * srcptr2,
+	  sgl_floating_point * dstptr, unsigned int *status)
+{
+	register unsigned int opnd1, opnd2, result;
+	register int opnd1_exponent, opnd2_exponent, dest_exponent, stepcount;
+	register boolean roundup = FALSE;
+
+	opnd1 = *srcptr1;
+	opnd2 = *srcptr2;
+	/*
+	 * check first operand for NaN's or infinity
+	 */
+	if ((opnd1_exponent = Sgl_exponent(opnd1)) == SGL_INFINITY_EXPONENT) {
+		if (Sgl_iszero_mantissa(opnd1)) {
+			if (Sgl_isnotnan(opnd2)) {
+				/* invalid since first operand is infinity */
+				if (Is_invalidtrap_enabled()) 
+                                	return(INVALIDEXCEPTION);
+                                Set_invalidflag();
+                                Sgl_makequietnan(result);
+				*dstptr = result;
+				return(NOEXCEPTION);
+			}
+		}
+		else {
+                	/*
+                 	 * is NaN; signaling or quiet?
+                 	 */
+                	if (Sgl_isone_signaling(opnd1)) {
+                        	/* trap if INVALIDTRAP enabled */
+                        	if (Is_invalidtrap_enabled()) 
+                            		return(INVALIDEXCEPTION);
+                        	/* make NaN quiet */
+                        	Set_invalidflag();
+                        	Sgl_set_quiet(opnd1);
+                	}
+			/* 
+			 * is second operand a signaling NaN? 
+			 */
+			else if (Sgl_is_signalingnan(opnd2)) {
+                        	/* trap if INVALIDTRAP enabled */
+                        	if (Is_invalidtrap_enabled()) 
+                            		return(INVALIDEXCEPTION);
+                        	/* make NaN quiet */
+                        	Set_invalidflag();
+                        	Sgl_set_quiet(opnd2);
+                		*dstptr = opnd2;
+                		return(NOEXCEPTION);
+			}
+                	/*
+                 	 * return quiet NaN
+                 	 */
+                	*dstptr = opnd1;
+                	return(NOEXCEPTION);
+		}
+	} 
+	/*
+	 * check second operand for NaN's or infinity
+	 */
+	if ((opnd2_exponent = Sgl_exponent(opnd2)) == SGL_INFINITY_EXPONENT) {
+		if (Sgl_iszero_mantissa(opnd2)) {
+			/*
+			 * return first operand
+			 */
+                	*dstptr = opnd1;
+			return(NOEXCEPTION);
+		}
+                /*
+                 * is NaN; signaling or quiet?
+                 */
+                if (Sgl_isone_signaling(opnd2)) {
+                        /* trap if INVALIDTRAP enabled */
+                        if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
+                        /* make NaN quiet */
+                        Set_invalidflag();
+                        Sgl_set_quiet(opnd2);
+                }
+                /*
+                 * return quiet NaN
+                 */
+                *dstptr = opnd2;
+                return(NOEXCEPTION);
+	}
+	/*
+	 * check second operand for zero
+	 */
+	if (Sgl_iszero_exponentmantissa(opnd2)) {
+		/* invalid since second operand is zero */
+		if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
+                Set_invalidflag();
+                Sgl_makequietnan(result);
+		*dstptr = result;
+		return(NOEXCEPTION);
+	}
+
+	/* 
+	 * get sign of result
+	 */
+	result = opnd1;  
+
+	/* 
+	 * check for denormalized operands
+	 */
+	if (opnd1_exponent == 0) {
+		/* check for zero */
+		if (Sgl_iszero_mantissa(opnd1)) {
+			*dstptr = opnd1;
+			return(NOEXCEPTION);
+		}
+		/* normalize, then continue */
+		opnd1_exponent = 1;
+		Sgl_normalize(opnd1,opnd1_exponent);
+	}
+	else {
+		Sgl_clear_signexponent_set_hidden(opnd1);
+	}
+	if (opnd2_exponent == 0) {
+		/* normalize, then continue */
+		opnd2_exponent = 1;
+		Sgl_normalize(opnd2,opnd2_exponent);
+	}
+	else {
+		Sgl_clear_signexponent_set_hidden(opnd2);
+	}
+
+	/* find result exponent and divide step loop count */
+	dest_exponent = opnd2_exponent - 1;
+	stepcount = opnd1_exponent - opnd2_exponent;
+
+	/*
+	 * check for opnd1/opnd2 < 1
+	 */
+	if (stepcount < 0) {
+		/*
+		 * check for opnd1/opnd2 > 1/2
+		 *
+		 * In this case n will round to 1, so 
+		 *    r = opnd1 - opnd2 
+		 */
+		if (stepcount == -1 && Sgl_isgreaterthan(opnd1,opnd2)) {
+			Sgl_all(result) = ~Sgl_all(result);   /* set sign */
+			/* align opnd2 with opnd1 */
+			Sgl_leftshiftby1(opnd2); 
+			Sgl_subtract(opnd2,opnd1,opnd2);
+			/* now normalize */
+                	while (Sgl_iszero_hidden(opnd2)) {
+                        	Sgl_leftshiftby1(opnd2);
+                        	dest_exponent--;
+			}
+			Sgl_set_exponentmantissa(result,opnd2);
+			goto testforunderflow;
+		}
+		/*
+		 * opnd1/opnd2 <= 1/2
+		 *
+		 * In this case n will round to zero, so 
+		 *    r = opnd1
+		 */
+		Sgl_set_exponentmantissa(result,opnd1);
+		dest_exponent = opnd1_exponent;
+		goto testforunderflow;
+	}
+
+	/*
+	 * Generate result
+	 *
+	 * Do iterative subtract until remainder is less than operand 2.
+	 */
+	while (stepcount-- > 0 && Sgl_all(opnd1)) {
+		if (Sgl_isnotlessthan(opnd1,opnd2))
+			Sgl_subtract(opnd1,opnd2,opnd1);
+		Sgl_leftshiftby1(opnd1);
+	}
+	/*
+	 * Do last subtract, then determine which way to round if remainder 
+	 * is exactly 1/2 of opnd2 
+	 */
+	if (Sgl_isnotlessthan(opnd1,opnd2)) {
+		Sgl_subtract(opnd1,opnd2,opnd1);
+		roundup = TRUE;
+	}
+	if (stepcount > 0 || Sgl_iszero(opnd1)) {
+		/* division is exact, remainder is zero */
+		Sgl_setzero_exponentmantissa(result);
+		*dstptr = result;
+		return(NOEXCEPTION);
+	}
+
+	/* 
+	 * Check for cases where opnd1/opnd2 < n 
+	 *
+	 * In this case the result's sign will be opposite that of
+	 * opnd1.  The mantissa also needs some correction.
+	 */
+	Sgl_leftshiftby1(opnd1);
+	if (Sgl_isgreaterthan(opnd1,opnd2)) {
+		Sgl_invert_sign(result);
+		Sgl_subtract((opnd2<<1),opnd1,opnd1);
+	}
+	/* check for remainder being exactly 1/2 of opnd2 */
+	else if (Sgl_isequal(opnd1,opnd2) && roundup) { 
+		Sgl_invert_sign(result);
+	}
+
+	/* normalize result's mantissa */
+        while (Sgl_iszero_hidden(opnd1)) {
+                dest_exponent--;
+                Sgl_leftshiftby1(opnd1);
+        }
+	Sgl_set_exponentmantissa(result,opnd1);
+
+        /* 
+         * Test for underflow
+         */
+    testforunderflow:
+	if (dest_exponent <= 0) {
+                /* trap if UNDERFLOWTRAP enabled */
+                if (Is_underflowtrap_enabled()) {
+                        /*
+                         * Adjust bias of result
+                         */
+                        Sgl_setwrapped_exponent(result,dest_exponent,unfl);
+			*dstptr = result;
+			/* frem is always exact */
+			return(UNDERFLOWEXCEPTION);
+                }
+                /*
+                 * denormalize result or set to signed zero
+                 */
+                if (dest_exponent >= (1 - SGL_P)) {
+			Sgl_rightshift_exponentmantissa(result,1-dest_exponent);
+                }
+                else {
+			Sgl_setzero_exponentmantissa(result);
+		}
+	}
+	else Sgl_set_exponent(result,dest_exponent);
+	*dstptr = result;
+	return(NOEXCEPTION);
+}