From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35399) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eoSDe-000420-Ew for qemu-devel@nongnu.org; Wed, 21 Feb 2018 06:05:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eoSDd-0006ka-By for qemu-devel@nongnu.org; Wed, 21 Feb 2018 06:05:50 -0500 Received: from mail-wr0-x242.google.com ([2a00:1450:400c:c0c::242]:34347) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1eoSDd-0006k7-4y for qemu-devel@nongnu.org; Wed, 21 Feb 2018 06:05:49 -0500 Received: by mail-wr0-x242.google.com with SMTP id m5so3302538wrg.1 for ; Wed, 21 Feb 2018 03:05:49 -0800 (PST) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Wed, 21 Feb 2018 11:05:19 +0000 Message-Id: <20180221110523.859-20-alex.bennee@linaro.org> In-Reply-To: <20180221110523.859-1-alex.bennee@linaro.org> References: <20180221110523.859-1-alex.bennee@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PULL 19/22] fpu/softfloat: re-factor scalbn List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: peter.maydell@linaro.org Cc: qemu-devel@nongnu.org, =?UTF-8?q?Alex=20Benn=C3=A9e?= , Aurelien Jarno This is one of the simpler manipulations you could make to a floating point number. Signed-off-by: Alex Bennée Reviewed-by: Richard Henderson diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 4313d3a602..a07b8556b0 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -1663,6 +1663,39 @@ float64 uint16_to_float64(uint16_t a, float_status *status) return uint64_to_float64(a, status); } +/* Multiply A by 2 raised to the power N. */ +static FloatParts scalbn_decomposed(FloatParts a, int n, float_status *s) +{ + if (unlikely(is_nan(a.cls))) { + return return_nan(a, s); + } + if (a.cls == float_class_normal) { + a.exp += n; + } + return a; +} + +float16 float16_scalbn(float16 a, int n, float_status *status) +{ + FloatParts pa = float16_unpack_canonical(a, status); + FloatParts pr = scalbn_decomposed(pa, n, status); + return float16_round_pack_canonical(pr, status); +} + +float32 float32_scalbn(float32 a, int n, float_status *status) +{ + FloatParts pa = float32_unpack_canonical(a, status); + FloatParts pr = scalbn_decomposed(pa, n, status); + return float32_round_pack_canonical(pr, status); +} + +float64 float64_scalbn(float64 a, int n, float_status *status) +{ + FloatParts pa = float64_unpack_canonical(a, status); + FloatParts pr = scalbn_decomposed(pa, n, status); + return float64_round_pack_canonical(pr, status); +} + /*---------------------------------------------------------------------------- | Takes a 64-bit fixed-point value `absZ' with binary point between bits 6 | and 7, and returns the properly rounded 32-bit integer corresponding to the @@ -6986,79 +7019,6 @@ MINMAX(32) MINMAX(64) -/* Multiply A by 2 raised to the power N. */ -float32 float32_scalbn(float32 a, int n, float_status *status) -{ - flag aSign; - int16_t aExp; - uint32_t aSig; - - a = float32_squash_input_denormal(a, status); - aSig = extractFloat32Frac( a ); - aExp = extractFloat32Exp( a ); - aSign = extractFloat32Sign( a ); - - if ( aExp == 0xFF ) { - if ( aSig ) { - return propagateFloat32NaN(a, a, status); - } - return a; - } - if (aExp != 0) { - aSig |= 0x00800000; - } else if (aSig == 0) { - return a; - } else { - aExp++; - } - - if (n > 0x200) { - n = 0x200; - } else if (n < -0x200) { - n = -0x200; - } - - aExp += n - 1; - aSig <<= 7; - return normalizeRoundAndPackFloat32(aSign, aExp, aSig, status); -} - -float64 float64_scalbn(float64 a, int n, float_status *status) -{ - flag aSign; - int16_t aExp; - uint64_t aSig; - - a = float64_squash_input_denormal(a, status); - aSig = extractFloat64Frac( a ); - aExp = extractFloat64Exp( a ); - aSign = extractFloat64Sign( a ); - - if ( aExp == 0x7FF ) { - if ( aSig ) { - return propagateFloat64NaN(a, a, status); - } - return a; - } - if (aExp != 0) { - aSig |= LIT64( 0x0010000000000000 ); - } else if (aSig == 0) { - return a; - } else { - aExp++; - } - - if (n > 0x1000) { - n = 0x1000; - } else if (n < -0x1000) { - n = -0x1000; - } - - aExp += n - 1; - aSig <<= 10; - return normalizeRoundAndPackFloat64(aSign, aExp, aSig, status); -} - floatx80 floatx80_scalbn(floatx80 a, int n, float_status *status) { flag aSign; diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h index 3e6fdd756a..52621e0b79 100644 --- a/include/fpu/softfloat.h +++ b/include/fpu/softfloat.h @@ -244,6 +244,7 @@ float16 float16_sub(float16, float16, float_status *status); float16 float16_mul(float16, float16, float_status *status); float16 float16_muladd(float16, float16, float16, int, float_status *status); float16 float16_div(float16, float16, float_status *status); +float16 float16_scalbn(float16, int, float_status *status); int float16_is_quiet_nan(float16, float_status *status); int float16_is_signaling_nan(float16, float_status *status); -- 2.15.1