1 files changed, 86 insertions, 0 deletions
diff --git a/arch/ia64/lib/idiv32.S b/arch/ia64/lib/idiv32.S
new file mode 100644
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+++ b/arch/ia64/lib/idiv32.S
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+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2000 Hewlett-Packard Co
+ * Copyright (C) 2000 David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * 32-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.goodreads.com/book/show/2019887.Ia_64_and_Elementary_Functions)
+ */
+
+#include <asm/asmmacro.h>
+#include <asm/export.h>
+
+#ifdef MODULO
+# define OP	mod
+#else
+# define OP	div
+#endif
+
+#ifdef UNSIGNED
+# define SGN	u
+# define EXTEND	zxt4
+# 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 EXTEND	sxt4
+# 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,si3))
+
+GLOBAL_ENTRY(NAME)
+	.regstk 2,0,0,0
+	// Transfer inputs to FP registers.
+	mov r2 = 0xffdd			// r2 = -34 + 65535 (fp reg format bias)
+	EXTEND in0 = in0		// in0 = a
+	EXTEND in1 = in1		// in1 = b
+	;;
+	setf.sig f8 = in0
+	setf.sig f9 = in1
+#ifdef MODULO
+	sub in1 = r0, in1		// in1 = -b
+#endif
+	;;
+	// Convert the inputs to FP, to avoid FP software-assist faults.
+	INT_TO_FP(f8, f8)
+	INT_TO_FP(f9, f9)
+	;;
+	setf.exp f7 = r2		// f7 = 2^-34
+	frcpa.s1 f6, p6 = f8, f9	// y0 = frcpa(b)
+	;;
+(p6)	fmpy.s1 f8 = f8, f6		// q0 = a*y0
+(p6)	fnma.s1 f6 = f9, f6, f1		// e0 = -b*y0 + 1 
+	;;
+#ifdef MODULO
+	setf.sig f9 = in1		// f9 = -b
+#endif
+(p6)	fma.s1 f8 = f6, f8, f8		// q1 = e0*q0 + q0
+(p6)	fma.s1 f6 = f6, f6, f7		// e1 = e0*e0 + 2^-34
+	;;
+#ifdef MODULO
+	setf.sig f7 = in0
+#endif
+(p6)	fma.s1 f6 = f6, f8, f8		// q2 = e1*q1 + q1
+	;;
+	FP_TO_INT(f6, f6)		// q = trunc(q2)
+	;;
+#ifdef MODULO
+	xma.l f6 = f6, f9, f7		// r = q*(-b) + a
+	;;
+#endif
+	getf.sig r8 = f6		// transfer result to result register
+	br.ret.sptk.many rp
+END(NAME)
+EXPORT_SYMBOL(NAME)