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Diffstat (limited to 'arch/ia64/lib/idiv32.S')
| -rw-r--r-- | arch/ia64/lib/idiv32.S | 86 |
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 index 0000000000..83586fbc51 --- /dev/null +++ b/arch/ia64/lib/idiv32.S @@ -0,0 +1,86 @@ +/* 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 <linux/export.h> +#include <asm/asmmacro.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) |