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

• Lines: 298
• Date: Thu Nov 28 15:53:10 2002
• Orig file: linux-2.4.19/arch/parisc/math-emu/dfrem.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/parisc/math-emu/dfrem.c linux-2.4.20/arch/parisc/math-emu/dfrem.c
@@ -0,0 +1,297 @@
+/*
+ * 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/dfrem.c		$Revision: 1.1 $
+ *
+ *  Purpose:
+ *	Double Precision Floating-point Remainder
+ *
+ *  External Interfaces:
+ *	dbl_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 "dbl_float.h"
+
+/*
+ *  Double Precision Floating-point Remainder
+ */
+
+int
+dbl_frem (dbl_floating_point * srcptr1, dbl_floating_point * srcptr2,
+	  dbl_floating_point * dstptr, unsigned int *status)
+{
+	register unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2;
+	register unsigned int resultp1, resultp2;
+	register int opnd1_exponent, opnd2_exponent, dest_exponent, stepcount;
+	register boolean roundup = FALSE;
+
+	Dbl_copyfromptr(srcptr1,opnd1p1,opnd1p2);
+	Dbl_copyfromptr(srcptr2,opnd2p1,opnd2p2);
+	/*
+	 * check first operand for NaN's or infinity
+	 */
+	if ((opnd1_exponent = Dbl_exponent(opnd1p1)) == DBL_INFINITY_EXPONENT) {
+		if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
+			if (Dbl_isnotnan(opnd2p1,opnd2p2)) {
+				/* invalid since first operand is infinity */
+				if (Is_invalidtrap_enabled()) 
+                                	return(INVALIDEXCEPTION);
+                                Set_invalidflag();
+                                Dbl_makequietnan(resultp1,resultp2);
+				Dbl_copytoptr(resultp1,resultp2,dstptr);
+				return(NOEXCEPTION);
+			}
+		}
+		else {
+                	/*
+                 	 * is NaN; signaling or quiet?
+                 	 */
+                	if (Dbl_isone_signaling(opnd1p1)) {
+                        	/* trap if INVALIDTRAP enabled */
+                        	if (Is_invalidtrap_enabled()) 
+                            		return(INVALIDEXCEPTION);
+                        	/* make NaN quiet */
+                        	Set_invalidflag();
+                        	Dbl_set_quiet(opnd1p1);
+                	}
+			/* 
+			 * is second operand a signaling NaN? 
+			 */
+			else if (Dbl_is_signalingnan(opnd2p1)) {
+                        	/* trap if INVALIDTRAP enabled */
+                        	if (Is_invalidtrap_enabled()) 
+                            		return(INVALIDEXCEPTION);
+                        	/* make NaN quiet */
+                        	Set_invalidflag();
+                        	Dbl_set_quiet(opnd2p1);
+				Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
+                		return(NOEXCEPTION);
+			}
+                	/*
+                 	 * return quiet NaN
+                 	 */
+			Dbl_copytoptr(opnd1p1,opnd1p2,dstptr);
+                	return(NOEXCEPTION);
+		}
+	} 
+	/*
+	 * check second operand for NaN's or infinity
+	 */
+	if ((opnd2_exponent = Dbl_exponent(opnd2p1)) == DBL_INFINITY_EXPONENT) {
+		if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) {
+			/*
+			 * return first operand
+			 */
+			Dbl_copytoptr(opnd1p1,opnd1p2,dstptr);
+			return(NOEXCEPTION);
+		}
+                /*
+                 * is NaN; signaling or quiet?
+                 */
+                if (Dbl_isone_signaling(opnd2p1)) {
+                        /* trap if INVALIDTRAP enabled */
+                        if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
+                        /* make NaN quiet */
+                        Set_invalidflag();
+                        Dbl_set_quiet(opnd2p1);
+                }
+                /*
+                 * return quiet NaN
+                 */
+		Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
+                return(NOEXCEPTION);
+	}
+	/*
+	 * check second operand for zero
+	 */
+	if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) {
+		/* invalid since second operand is zero */
+		if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
+                Set_invalidflag();
+                Dbl_makequietnan(resultp1,resultp2);
+		Dbl_copytoptr(resultp1,resultp2,dstptr);
+		return(NOEXCEPTION);
+	}
+
+	/* 
+	 * get sign of result
+	 */
+	resultp1 = opnd1p1;  
+
+	/* 
+	 * check for denormalized operands
+	 */
+	if (opnd1_exponent == 0) {
+		/* check for zero */
+		if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
+			Dbl_copytoptr(opnd1p1,opnd1p2,dstptr);
+			return(NOEXCEPTION);
+		}
+		/* normalize, then continue */
+		opnd1_exponent = 1;
+		Dbl_normalize(opnd1p1,opnd1p2,opnd1_exponent);
+	}
+	else {
+		Dbl_clear_signexponent_set_hidden(opnd1p1);
+	}
+	if (opnd2_exponent == 0) {
+		/* normalize, then continue */
+		opnd2_exponent = 1;
+		Dbl_normalize(opnd2p1,opnd2p2,opnd2_exponent);
+	}
+	else {
+		Dbl_clear_signexponent_set_hidden(opnd2p1);
+	}
+
+	/* 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 && 
+		    Dbl_isgreaterthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) {
+			/* set sign */
+			Dbl_allp1(resultp1) = ~Dbl_allp1(resultp1);
+			/* align opnd2 with opnd1 */
+			Dbl_leftshiftby1(opnd2p1,opnd2p2); 
+			Dbl_subtract(opnd2p1,opnd2p2,opnd1p1,opnd1p2,
+			 opnd2p1,opnd2p2);
+			/* now normalize */
+                	while (Dbl_iszero_hidden(opnd2p1)) {
+                        	Dbl_leftshiftby1(opnd2p1,opnd2p2);
+                        	dest_exponent--;
+			}
+			Dbl_set_exponentmantissa(resultp1,resultp2,opnd2p1,opnd2p2);
+			goto testforunderflow;
+		}
+		/*
+		 * opnd1/opnd2 <= 1/2
+		 *
+		 * In this case n will round to zero, so 
+		 *    r = opnd1
+		 */
+		Dbl_set_exponentmantissa(resultp1,resultp2,opnd1p1,opnd1p2);
+		dest_exponent = opnd1_exponent;
+		goto testforunderflow;
+	}
+
+	/*
+	 * Generate result
+	 *
+	 * Do iterative subtract until remainder is less than operand 2.
+	 */
+	while (stepcount-- > 0 && (Dbl_allp1(opnd1p1) || Dbl_allp2(opnd1p2))) {
+		if (Dbl_isnotlessthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) {
+			Dbl_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2,opnd1p1,opnd1p2);
+		}
+		Dbl_leftshiftby1(opnd1p1,opnd1p2);
+	}
+	/*
+	 * Do last subtract, then determine which way to round if remainder 
+	 * is exactly 1/2 of opnd2 
+	 */
+	if (Dbl_isnotlessthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) {
+		Dbl_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2,opnd1p1,opnd1p2);
+		roundup = TRUE;
+	}
+	if (stepcount > 0 || Dbl_iszero(opnd1p1,opnd1p2)) {
+		/* division is exact, remainder is zero */
+		Dbl_setzero_exponentmantissa(resultp1,resultp2);
+		Dbl_copytoptr(resultp1,resultp2,dstptr);
+		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.
+	 */
+	Dbl_leftshiftby1(opnd1p1,opnd1p2);
+	if (Dbl_isgreaterthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) {
+		Dbl_invert_sign(resultp1);
+		Dbl_leftshiftby1(opnd2p1,opnd2p2);
+		Dbl_subtract(opnd2p1,opnd2p2,opnd1p1,opnd1p2,opnd1p1,opnd1p2);
+	}
+	/* check for remainder being exactly 1/2 of opnd2 */
+	else if (Dbl_isequal(opnd1p1,opnd1p2,opnd2p1,opnd2p2) && roundup) { 
+		Dbl_invert_sign(resultp1);
+	}
+
+	/* normalize result's mantissa */
+        while (Dbl_iszero_hidden(opnd1p1)) {
+                dest_exponent--;
+                Dbl_leftshiftby1(opnd1p1,opnd1p2);
+        }
+	Dbl_set_exponentmantissa(resultp1,resultp2,opnd1p1,opnd1p2);
+
+        /* 
+         * Test for underflow
+         */
+    testforunderflow:
+	if (dest_exponent <= 0) {
+                /* trap if UNDERFLOWTRAP enabled */
+                if (Is_underflowtrap_enabled()) {
+                        /*
+                         * Adjust bias of result
+                         */
+                        Dbl_setwrapped_exponent(resultp1,dest_exponent,unfl);
+			/* frem is always exact */
+			Dbl_copytoptr(resultp1,resultp2,dstptr);
+			return(UNDERFLOWEXCEPTION);
+                }
+                /*
+                 * denormalize result or set to signed zero
+                 */
+                if (dest_exponent >= (1 - DBL_P)) {
+			Dbl_rightshift_exponentmantissa(resultp1,resultp2,
+			 1-dest_exponent);
+                }
+                else {
+			Dbl_setzero_exponentmantissa(resultp1,resultp2);
+		}
+	}
+	else Dbl_set_exponent(resultp1,dest_exponent);
+	Dbl_copytoptr(resultp1,resultp2,dstptr);
+	return(NOEXCEPTION);
+}