.file "truncf.s"

// Copyright (c) 2000 - 2003, Intel Corporation

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//

// Contributed 2000 by the Intel Numerics Group, Intel Corporation

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// History

//==============================================================

// 07/07/00 Created

// 05/20/02 Cleaned up namespace and sf0 syntax

// 01/20/03 Improved performance and reduced code size

//==============================================================

// API

//==============================================================

// float truncf(float x)

//==============================================================

// general input registers:

// r14 - r18

rExpBias   = r14

rSignexp   = r15

rExp       = r16

rExpMask   = r17

rBigexp    = r18

// floating-point registers:

// f8 - f10

fXtruncInt = f9

fNormX     = f10

// predicate registers used:

// p6, p7

// Overview of operation

//==============================================================

// float truncf(float x)

// Return an integer value (represented as a float) less than or

// equal to x in magnitude.

// This is x rounded toward zero to an integral value.

//==============================================================

// double_extended

// if the exponent is > 1003e => 3F(true) = 63(decimal)

// we have a significand of 64 bits 1.63-bits.

// If we multiply by 2^63, we no longer have a fractional part

// So input is an integer value already.

// double

// if the exponent is >= 10033 => 34(true) = 52(decimal)

// 34 + 3ff = 433

// we have a significand of 53 bits 1.52-bits. (implicit 1)

// If we multiply by 2^52, we no longer have a fractional part

// So input is an integer value already.

// single

// if the exponent is > 10016 => 17(true) = 23(decimal)

// we have a significand of 24 bits 1.23-bits. (implicit 1)

// If we multiply by 2^23, we no longer have a fractional part

// So input is an integer value already.

.section .text

GLOBAL_LIBM_ENTRY(truncf)

{ .mfi

      getf.exp         rSignexp  = f8        // Get signexp, recompute if unorm

      fcvt.fx.trunc.s1 fXtruncInt  = f8      // Convert to int in significand

      addl             rBigexp = 0x10016, r0 // Set exponent at which is integer

}

{ .mfi

      mov              rExpBias    = 0x0FFFF // Form exponent bias

      fnorm.s1         fNormX  = f8          // Normalize input

      mov              rExpMask    = 0x1FFFF // Form exponent mask

}

;;

{ .mfi

      nop.m            0

      fclass.m         p7,p0 = f8, 0x0b      // Test x unorm

      nop.i            0

}

;;

{ .mfb

      nop.m            0

      fclass.m         p6,p0 = f8, 0x1e3     // Test x natval, nan, inf

(p7)  br.cond.spnt     TRUNC_UNORM           // Branch if x unorm

}

;;

TRUNC_COMMON:

// Return here from TRUNC_UNORM

{ .mfb

      and              rExp = rSignexp, rExpMask // Get biased exponent

(p6)  fma.s.s0         f8 = f8, f1, f0       // Result if x natval, nan, inf

(p6)  br.ret.spnt      b0                    // Exit if x natval, nan, inf

}

;;

{ .mfi

      cmp.lt           p6,p0 = rExp, rExpBias // Is |x| < 1?

      fcvt.xf          f8 = fXtruncInt        // Result, assume 1 <= |x| < 2^23

      cmp.ge           p7,p0 = rExp, rBigexp  // Is |x| >= 2^23?

}

;;

// We must correct result if |x| < 1, or |x| >= 2^23

.pred.rel "mutex",p6,p7

{ .mfi

      nop.m            0

(p6)  fmerge.s         f8 = fNormX, f0        // If |x| < 1, result sgn(x)*0

      nop.i            0

}

{ .mfb

      nop.m            0

(p7)  fma.s.s0         f8 = fNormX, f1, f0    // If |x| >= 2^23, result x

      br.ret.sptk      b0                     // Exit main path

}

;;

TRUNC_UNORM:

// Here if x unorm

{ .mfb

      getf.exp         rSignexp  = fNormX     // Get signexp, recompute if unorm

      fcmp.eq.s0       p7,p0 = f8, f0         // Dummy op to set denormal flag

      br.cond.sptk     TRUNC_COMMON           // Return to main path

}

;;

GLOBAL_LIBM_END(truncf)

libm_alias_float_other (trunc, trunc)