From ffc51161f327bd77a9650f4bc70908297343d5fa Mon Sep 17 00:00:00 2001 From: Lioncash Date: Mon, 11 May 2015 14:46:31 -0400 Subject: vfp: Handle flush-to-zero mode. --- src/core/arm/skyeye_common/vfp/vfp_helper.h | 117 +++++++++++++++------------- 1 file changed, 65 insertions(+), 52 deletions(-) (limited to 'src/core/arm/skyeye_common/vfp/vfp_helper.h') diff --git a/src/core/arm/skyeye_common/vfp/vfp_helper.h b/src/core/arm/skyeye_common/vfp/vfp_helper.h index 6b3dae28..ccc0212a 100644 --- a/src/core/arm/skyeye_common/vfp/vfp_helper.h +++ b/src/core/arm/skyeye_common/vfp/vfp_helper.h @@ -35,6 +35,7 @@ #include #include "common/common_types.h" #include "core/arm/skyeye_common/armdefs.h" +#include "core/arm/skyeye_common/vfp/asm_vfp.h" #define do_div(n, base) {n/=base;} @@ -236,33 +237,6 @@ struct vfp_single { #define vfp_single_packed_exponent(v) (((v) >> VFP_SINGLE_MANTISSA_BITS) & ((1 << VFP_SINGLE_EXPONENT_BITS) - 1)) #define vfp_single_packed_mantissa(v) ((v) & ((1 << VFP_SINGLE_MANTISSA_BITS) - 1)) -// Unpack a single-precision float. Note that this returns the magnitude -// of the single-precision float mantissa with the 1. if necessary, -// aligned to bit 30. -static inline void vfp_single_unpack(vfp_single* s, s32 val) -{ - u32 significand; - - s->sign = vfp_single_packed_sign(val) >> 16, - s->exponent = vfp_single_packed_exponent(val); - - significand = (u32) val; - significand = (significand << (32 - VFP_SINGLE_MANTISSA_BITS)) >> 2; - if (s->exponent && s->exponent != 255) - significand |= 0x40000000; - s->significand = significand; -} - -// Re-pack a single-precision float. This assumes that the float is -// already normalised such that the MSB is bit 30, _not_ bit 31. -static inline s32 vfp_single_pack(vfp_single* s) -{ - u32 val = (s->sign << 16) + - (s->exponent << VFP_SINGLE_MANTISSA_BITS) + - (s->significand >> VFP_SINGLE_LOW_BITS); - return (s32)val; -} - enum : u32 { VFP_NUMBER = (1 << 0), VFP_ZERO = (1 << 1), @@ -294,6 +268,39 @@ static inline int vfp_single_type(vfp_single* s) return type; } +// Unpack a single-precision float. Note that this returns the magnitude +// of the single-precision float mantissa with the 1. if necessary, +// aligned to bit 30. +static inline void vfp_single_unpack(vfp_single* s, s32 val, u32* fpscr) +{ + s->sign = vfp_single_packed_sign(val) >> 16, + s->exponent = vfp_single_packed_exponent(val); + + u32 significand = ((u32)val << (32 - VFP_SINGLE_MANTISSA_BITS)) >> 2; + if (s->exponent && s->exponent != 255) + significand |= 0x40000000; + s->significand = significand; + + // If flush-to-zero mode is enabled, turn the denormal into zero. + // On a VFPv2 architecture, the sign of the zero is always positive. + if ((*fpscr & FPSCR_FLUSH_TO_ZERO) != 0 && (vfp_single_type(s) & VFP_DENORMAL) != 0) { + s->sign = 0; + s->exponent = 0; + s->significand = 0; + *fpscr |= FPSCR_IDC; + } +} + +// Re-pack a single-precision float. This assumes that the float is +// already normalised such that the MSB is bit 30, _not_ bit 31. +static inline s32 vfp_single_pack(vfp_single* s) +{ + u32 val = (s->sign << 16) + + (s->exponent << VFP_SINGLE_MANTISSA_BITS) + + (s->significand >> VFP_SINGLE_LOW_BITS); + return (s32)val; +} + u32 vfp_single_normaliseround(ARMul_State* state, int sd, vfp_single* vs, u32 fpscr, u32 exceptions, const char* func); @@ -328,24 +335,49 @@ struct vfp_double { #define vfp_double_packed_exponent(v) (((v) >> VFP_DOUBLE_MANTISSA_BITS) & ((1 << VFP_DOUBLE_EXPONENT_BITS) - 1)) #define vfp_double_packed_mantissa(v) ((v) & ((1ULL << VFP_DOUBLE_MANTISSA_BITS) - 1)) +static inline int vfp_double_type(vfp_double* s) +{ + int type = VFP_NUMBER; + if (s->exponent == 2047) { + if (s->significand == 0) + type = VFP_INFINITY; + else if (s->significand & VFP_DOUBLE_SIGNIFICAND_QNAN) + type = VFP_QNAN; + else + type = VFP_SNAN; + } else if (s->exponent == 0) { + if (s->significand == 0) + type |= VFP_ZERO; + else + type |= VFP_DENORMAL; + } + return type; +} + // Unpack a double-precision float. Note that this returns the magnitude // of the double-precision float mantissa with the 1. if necessary, // aligned to bit 62. -static inline void vfp_double_unpack(vfp_double* s, s64 val) +static inline void vfp_double_unpack(vfp_double* s, s64 val, u32* fpscr) { - u64 significand; - s->sign = vfp_double_packed_sign(val) >> 48; s->exponent = vfp_double_packed_exponent(val); - significand = (u64) val; - significand = (significand << (64 - VFP_DOUBLE_MANTISSA_BITS)) >> 2; + u64 significand = ((u64)val << (64 - VFP_DOUBLE_MANTISSA_BITS)) >> 2; if (s->exponent && s->exponent != 2047) significand |= (1ULL << 62); s->significand = significand; + + // If flush-to-zero mode is enabled, turn the denormal into zero. + // On a VFPv2 architecture, the sign of the zero is always positive. + if ((*fpscr & FPSCR_FLUSH_TO_ZERO) != 0 && (vfp_double_type(s) & VFP_DENORMAL) != 0) { + s->sign = 0; + s->exponent = 0; + s->significand = 0; + *fpscr |= FPSCR_IDC; + } } -// Re-pack a double-precision float. This assumes that the float is +// Re-pack a double-precision float. This assumes that the float is // already normalised such that the MSB is bit 30, _not_ bit 31. static inline s64 vfp_double_pack(vfp_double* s) { @@ -355,25 +387,6 @@ static inline s64 vfp_double_pack(vfp_double* s) return (s64)val; } -static inline int vfp_double_type(vfp_double* s) -{ - int type = VFP_NUMBER; - if (s->exponent == 2047) { - if (s->significand == 0) - type = VFP_INFINITY; - else if (s->significand & VFP_DOUBLE_SIGNIFICAND_QNAN) - type = VFP_QNAN; - else - type = VFP_SNAN; - } else if (s->exponent == 0) { - if (s->significand == 0) - type |= VFP_ZERO; - else - type |= VFP_DENORMAL; - } - return type; -} - u32 vfp_estimate_sqrt_significand(u32 exponent, u32 significand); // A special flag to tell the normalisation code not to normalise. -- cgit v1.2.3