From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51451) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eYsvp-0006fS-Nm for qemu-devel@nongnu.org; Tue, 09 Jan 2018 07:23:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eYsvo-0006g2-Nl for qemu-devel@nongnu.org; Tue, 09 Jan 2018 07:23:05 -0500 Received: from mail-wr0-x241.google.com ([2a00:1450:400c:c0c::241]:47022) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1eYsvo-0006eU-Hl for qemu-devel@nongnu.org; Tue, 09 Jan 2018 07:23:04 -0500 Received: by mail-wr0-x241.google.com with SMTP id g21so8109645wrb.13 for ; Tue, 09 Jan 2018 04:23:04 -0800 (PST) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Tue, 9 Jan 2018 12:22:42 +0000 Message-Id: <20180109122252.17670-11-alex.bennee@linaro.org> In-Reply-To: <20180109122252.17670-1-alex.bennee@linaro.org> References: <20180109122252.17670-1-alex.bennee@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH v2 10/20] fpu/softfloat: define decompose structures List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: richard.henderson@linaro.org, peter.maydell@linaro.org, laurent@vivier.eu, bharata@linux.vnet.ibm.com, andrew@andrewdutcher.com Cc: qemu-devel@nongnu.org, =?UTF-8?q?Alex=20Benn=C3=A9e?= , Aurelien Jarno These structures pave the way for generic softfloat helper routines that will operate on fully decomposed numbers. Signed-off-by: Alex Bennée Signed-off-by: Richard Henderson --- fpu/softfloat.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 69 insertions(+), 1 deletion(-) diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 59afe81d06..fcba28d3f8 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -83,7 +83,7 @@ this code that are retained. * target-dependent and needs the TARGET_* macros. */ #include "qemu/osdep.h" - +#include "qemu/bitops.h" #include "fpu/softfloat.h" /* We only need stdlib for abort() */ @@ -186,6 +186,74 @@ static inline flag extractFloat64Sign(float64 a) return float64_val(a) >> 63; } +/*---------------------------------------------------------------------------- +| Classify a floating point number. +*----------------------------------------------------------------------------*/ + +typedef enum { + float_class_unclassified, + float_class_zero, + float_class_normal, + float_class_inf, + float_class_qnan, + float_class_snan, + float_class_dnan, + float_class_msnan, /* maybe silenced */ +} float_class; + +/*---------------------------------------------------------------------------- +| Structure holding all of the decomposed parts of a float. +| The exponent is unbiased and the fraction is normalized. +*----------------------------------------------------------------------------*/ + +typedef struct { + uint64_t frac : 64; + int exp : 32; + float_class cls : 8; + int : 23; + bool sign : 1; +} decomposed_parts; + +#define DECOMPOSED_BINARY_POINT (64 - 2) +#define DECOMPOSED_IMPLICIT_BIT (1ull << DECOMPOSED_BINARY_POINT) +#define DECOMPOSED_OVERFLOW_BIT (DECOMPOSED_IMPLICIT_BIT << 1) + +/* Structure holding all of the relevant parameters for a format. */ +typedef struct { + int exp_bias; + int exp_max; + int frac_shift; + uint64_t frac_lsb; + uint64_t frac_lsbm1; + uint64_t round_mask; + uint64_t roundeven_mask; +} decomposed_params; + +#define FRAC_PARAMS(F) \ + .frac_shift = F, \ + .frac_lsb = 1ull << (F), \ + .frac_lsbm1 = 1ull << ((F) - 1), \ + .round_mask = (1ull << (F)) - 1, \ + .roundeven_mask = (2ull << (F)) - 1 + +static const decomposed_params float16_params = { + .exp_bias = 0x0f, + .exp_max = 0x1f, + FRAC_PARAMS(DECOMPOSED_BINARY_POINT - 10) +}; + +static const decomposed_params float32_params = { + .exp_bias = 0x7f, + .exp_max = 0xff, + FRAC_PARAMS(DECOMPOSED_BINARY_POINT - 23) +}; + +static const decomposed_params float64_params = { + .exp_bias = 0x3ff, + .exp_max = 0x7ff, + FRAC_PARAMS(DECOMPOSED_BINARY_POINT - 52) +}; + /*---------------------------------------------------------------------------- | 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 -- 2.15.1