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

• Lines: 381
• Date: Thu Nov 28 15:53:10 2002
• Orig file: linux-2.4.19/arch/parisc/math-emu/sfmpy.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/parisc/math-emu/sfmpy.c linux-2.4.20/arch/parisc/math-emu/sfmpy.c
@@ -0,0 +1,380 @@
+/*
+ * 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/sfmpy.c		$Revision: 1.1 $
+ *
+ *  Purpose:
+ *	Single Precision Floating-point Multiply
+ *
+ *  External Interfaces:
+ *	sgl_fmpy(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 Multiply
+ */
+
+int
+sgl_fmpy(
+    sgl_floating_point *srcptr1,
+    sgl_floating_point *srcptr2,
+    sgl_floating_point *dstptr,
+    unsigned int *status)
+{
+	register unsigned int opnd1, opnd2, opnd3, result;
+	register int dest_exponent, count;
+	register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE;
+	boolean is_tiny;
+
+	opnd1 = *srcptr1;
+	opnd2 = *srcptr2;
+	/* 
+	 * set sign bit of result 
+	 */
+	if (Sgl_sign(opnd1) ^ Sgl_sign(opnd2)) Sgl_setnegativezero(result);  
+	else Sgl_setzero(result);
+	/*
+	 * check first operand for NaN's or infinity
+	 */
+	if (Sgl_isinfinity_exponent(opnd1)) {
+		if (Sgl_iszero_mantissa(opnd1)) {
+			if (Sgl_isnotnan(opnd2)) {
+				if (Sgl_iszero_exponentmantissa(opnd2)) {
+					/* 
+					 * invalid since operands are infinity 
+					 * and zero 
+					 */
+					if (Is_invalidtrap_enabled()) 
+                                		return(INVALIDEXCEPTION);
+                                	Set_invalidflag();
+                                	Sgl_makequietnan(result);
+					*dstptr = result;
+					return(NOEXCEPTION);
+				}
+				/*
+			 	 * return infinity
+			 	 */
+				Sgl_setinfinity_exponentmantissa(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 (Sgl_isinfinity_exponent(opnd2)) {
+		if (Sgl_iszero_mantissa(opnd2)) {
+			if (Sgl_iszero_exponentmantissa(opnd1)) {
+				/* invalid since operands are zero & infinity */
+				if (Is_invalidtrap_enabled()) 
+                                	return(INVALIDEXCEPTION);
+                                Set_invalidflag();
+                                Sgl_makequietnan(opnd2);
+				*dstptr = opnd2;
+				return(NOEXCEPTION);
+			}
+			/*
+			 * return infinity
+			 */
+			Sgl_setinfinity_exponentmantissa(result);
+			*dstptr = result;
+			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);
+	}
+	/*
+	 * Generate exponent 
+	 */
+	dest_exponent = Sgl_exponent(opnd1) + Sgl_exponent(opnd2) - SGL_BIAS;
+
+	/*
+	 * Generate mantissa
+	 */
+	if (Sgl_isnotzero_exponent(opnd1)) {
+		/* set hidden bit */
+		Sgl_clear_signexponent_set_hidden(opnd1);
+	}
+	else {
+		/* check for zero */
+		if (Sgl_iszero_mantissa(opnd1)) {
+			Sgl_setzero_exponentmantissa(result);
+			*dstptr = result;
+			return(NOEXCEPTION);
+		}
+                /* is denormalized, adjust exponent */
+                Sgl_clear_signexponent(opnd1);
+		Sgl_leftshiftby1(opnd1);
+		Sgl_normalize(opnd1,dest_exponent);
+	}
+	/* opnd2 needs to have hidden bit set with msb in hidden bit */
+	if (Sgl_isnotzero_exponent(opnd2)) {
+		Sgl_clear_signexponent_set_hidden(opnd2);
+	}
+	else {
+		/* check for zero */
+		if (Sgl_iszero_mantissa(opnd2)) {
+			Sgl_setzero_exponentmantissa(result);
+			*dstptr = result;
+			return(NOEXCEPTION);
+		}
+                /* is denormalized; want to normalize */
+                Sgl_clear_signexponent(opnd2);
+                Sgl_leftshiftby1(opnd2);
+		Sgl_normalize(opnd2,dest_exponent);
+	}
+
+	/* Multiply two source mantissas together */
+
+	Sgl_leftshiftby4(opnd2);     /* make room for guard bits */
+	Sgl_setzero(opnd3);
+	/*
+	 * Four bits at a time are inspected in each loop, and a
+	 * simple shift and add multiply algorithm is used.
+	 */
+	for (count=1;count<SGL_P;count+=4) {
+		stickybit |= Slow4(opnd3);
+		Sgl_rightshiftby4(opnd3);
+		if (Sbit28(opnd1)) Sall(opnd3) += (Sall(opnd2) << 3);
+		if (Sbit29(opnd1)) Sall(opnd3) += (Sall(opnd2) << 2);
+		if (Sbit30(opnd1)) Sall(opnd3) += (Sall(opnd2) << 1);
+		if (Sbit31(opnd1)) Sall(opnd3) += Sall(opnd2);
+		Sgl_rightshiftby4(opnd1);
+	}
+	/* make sure result is left-justified */
+	if (Sgl_iszero_sign(opnd3)) {
+		Sgl_leftshiftby1(opnd3);
+	}
+	else {
+		/* result mantissa >= 2. */
+		dest_exponent++;
+	}
+	/* check for denormalized result */
+	while (Sgl_iszero_sign(opnd3)) {
+		Sgl_leftshiftby1(opnd3);
+		dest_exponent--;
+	}
+	/*
+	 * check for guard, sticky and inexact bits
+	 */
+	stickybit |= Sgl_all(opnd3) << (SGL_BITLENGTH - SGL_EXP_LENGTH + 1);
+	guardbit = Sbit24(opnd3);
+	inexact = guardbit | stickybit;
+
+	/* re-align mantissa */
+	Sgl_rightshiftby8(opnd3);
+
+	/* 
+	 * round result 
+	 */
+	if (inexact && (dest_exponent>0 || Is_underflowtrap_enabled())) {
+		Sgl_clear_signexponent(opnd3);
+		switch (Rounding_mode()) {
+			case ROUNDPLUS: 
+				if (Sgl_iszero_sign(result)) 
+					Sgl_increment(opnd3);
+				break;
+			case ROUNDMINUS: 
+				if (Sgl_isone_sign(result)) 
+					Sgl_increment(opnd3);
+				break;
+			case ROUNDNEAREST:
+				if (guardbit) {
+			   	if (stickybit || Sgl_isone_lowmantissa(opnd3))
+			      	Sgl_increment(opnd3);
+				}
+		}
+		if (Sgl_isone_hidden(opnd3)) dest_exponent++;
+	}
+	Sgl_set_mantissa(result,opnd3);
+
+        /* 
+         * Test for overflow
+         */
+	if (dest_exponent >= SGL_INFINITY_EXPONENT) {
+                /* trap if OVERFLOWTRAP enabled */
+                if (Is_overflowtrap_enabled()) {
+                        /*
+                         * Adjust bias of result
+                         */
+			Sgl_setwrapped_exponent(result,dest_exponent,ovfl);
+			*dstptr = result;
+			if (inexact) 
+			    if (Is_inexacttrap_enabled())
+				return(OVERFLOWEXCEPTION | INEXACTEXCEPTION);
+			    else Set_inexactflag();
+			return(OVERFLOWEXCEPTION);
+                }
+		inexact = TRUE;
+		Set_overflowflag();
+                /* set result to infinity or largest number */
+		Sgl_setoverflow(result);
+	}
+        /* 
+         * Test for underflow
+         */
+	else 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;
+			if (inexact) 
+			    if (Is_inexacttrap_enabled())
+				return(UNDERFLOWEXCEPTION | INEXACTEXCEPTION);
+			    else Set_inexactflag();
+			return(UNDERFLOWEXCEPTION);
+                }
+
+		/* Determine if should set underflow flag */
+		is_tiny = TRUE;
+		if (dest_exponent == 0 && inexact) {
+			switch (Rounding_mode()) {
+			case ROUNDPLUS: 
+				if (Sgl_iszero_sign(result)) {
+					Sgl_increment(opnd3);
+					if (Sgl_isone_hiddenoverflow(opnd3))
+                			    is_tiny = FALSE;
+					Sgl_decrement(opnd3);
+				}
+				break;
+			case ROUNDMINUS: 
+				if (Sgl_isone_sign(result)) {
+					Sgl_increment(opnd3);
+					if (Sgl_isone_hiddenoverflow(opnd3))
+                			    is_tiny = FALSE;
+					Sgl_decrement(opnd3);
+				}
+				break;
+			case ROUNDNEAREST:
+				if (guardbit && (stickybit || 
+				    Sgl_isone_lowmantissa(opnd3))) {
+				      	Sgl_increment(opnd3);
+					if (Sgl_isone_hiddenoverflow(opnd3))
+                			    is_tiny = FALSE;
+					Sgl_decrement(opnd3);
+				}
+				break;
+			}
+		}
+
+                /*
+                 * denormalize result or set to signed zero
+                 */
+		stickybit = inexact;
+		Sgl_denormalize(opnd3,dest_exponent,guardbit,stickybit,inexact);
+
+		/* return zero or smallest number */
+		if (inexact) {
+			switch (Rounding_mode()) {
+			case ROUNDPLUS: 
+				if (Sgl_iszero_sign(result)) {
+					Sgl_increment(opnd3);
+				}
+				break;
+			case ROUNDMINUS: 
+				if (Sgl_isone_sign(result)) {
+					Sgl_increment(opnd3);
+				}
+				break;
+			case ROUNDNEAREST:
+				if (guardbit && (stickybit || 
+				    Sgl_isone_lowmantissa(opnd3))) {
+			      		Sgl_increment(opnd3);
+				}
+				break;
+			}
+                if (is_tiny) Set_underflowflag();
+		}
+		Sgl_set_exponentmantissa(result,opnd3);
+	}
+	else Sgl_set_exponent(result,dest_exponent);
+	*dstptr = result;
+
+	/* check for inexact */
+	if (inexact) {
+		if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
+		else Set_inexactflag();
+	}
+	return(NOEXCEPTION);
+}