Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / ia64 / lib / idiv64.S

diff --git a/kernel/arch/ia64/lib/idiv64.S b/kernel/arch/ia64/lib/idiv64.S
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+/*
+ * Copyright (C) 1999-2000 Hewlett-Packard Co
+ * Copyright (C) 1999-2000 David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * 64-bit integer division.
+ *
+ * This code is based on the application note entitled "Divide, Square Root
+ * and Remainder Algorithms for the IA-64 Architecture".  This document
+ * is available as Intel document number 248725-002 or via the web at
+ * http://developer.intel.com/software/opensource/numerics/
+ *
+ * For more details on the theory behind these algorithms, see "IA-64
+ * and Elementary Functions" by Peter Markstein; HP Professional Books
+ * (http://www.hp.com/go/retailbooks/)
+ */
+
+#include <asm/asmmacro.h>
+
+#ifdef MODULO
+# define OP    mod
+#else
+# define OP    div
+#endif
+
+#ifdef UNSIGNED
+# define SGN   u
+# define INT_TO_FP(a,b)        fcvt.xuf.s1 a=b
+# define FP_TO_INT(a,b)        fcvt.fxu.trunc.s1 a=b
+#else
+# define SGN
+# define INT_TO_FP(a,b)        fcvt.xf a=b
+# define FP_TO_INT(a,b)        fcvt.fx.trunc.s1 a=b
+#endif
+
+#define PASTE1(a,b)    a##b
+#define PASTE(a,b)     PASTE1(a,b)
+#define NAME           PASTE(PASTE(__,SGN),PASTE(OP,di3))
+
+GLOBAL_ENTRY(NAME)
+       .regstk 2,0,0,0
+       // Transfer inputs to FP registers.
+       setf.sig f8 = in0
+       setf.sig f9 = in1
+       ;;
+       // Convert the inputs to FP, to avoid FP software-assist faults.
+       INT_TO_FP(f8, f8)
+       INT_TO_FP(f9, f9)
+       ;;
+       frcpa.s1 f11, p6 = f8, f9       // y0 = frcpa(b)
+       ;;
+(p6)   fmpy.s1 f7 = f8, f11            // q0 = a*y0
+(p6)   fnma.s1 f6 = f9, f11, f1        // e0 = -b*y0 + 1
+       ;;
+(p6)   fma.s1 f10 = f7, f6, f7         // q1 = q0*e0 + q0
+(p6)   fmpy.s1 f7 = f6, f6             // e1 = e0*e0
+       ;;
+#ifdef MODULO
+       sub in1 = r0, in1               // in1 = -b
+#endif
+(p6)   fma.s1 f10 = f10, f7, f10       // q2 = q1*e1 + q1
+(p6)   fma.s1 f6 = f11, f6, f11        // y1 = y0*e0 + y0
+       ;;
+(p6)   fma.s1 f6 = f6, f7, f6          // y2 = y1*e1 + y1
+(p6)   fnma.s1 f7 = f9, f10, f8        // r = -b*q2 + a
+       ;;
+#ifdef MODULO
+       setf.sig f8 = in0               // f8 = a
+       setf.sig f9 = in1               // f9 = -b
+#endif
+(p6)   fma.s1 f11 = f7, f6, f10        // q3 = r*y2 + q2
+       ;;
+       FP_TO_INT(f11, f11)             // q = trunc(q3)
+       ;;
+#ifdef MODULO
+       xma.l f11 = f11, f9, f8         // r = q*(-b) + a
+       ;;
+#endif
+       getf.sig r8 = f11               // transfer result to result register
+       br.ret.sptk.many rp
+END(NAME)