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/*
* Helpers for emulation of FPU-related MIPS instructions.
*
* Copyright (C) 2004-2005 Jocelyn Mayer
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
#include "fpu/softfloat-helpers.h"
#include "cpu.h"
extern const FloatRoundMode ieee_rm[4];
uint32_t float_class_s(uint32_t arg, float_status *fst);
uint64_t float_class_d(uint64_t arg, float_status *fst);
static inline void restore_rounding_mode(CPUMIPSState *env)
{
set_float_rounding_mode(ieee_rm[env->active_fpu.fcr31 & 3],
&env->active_fpu.fp_status);
}
static inline void restore_flush_mode(CPUMIPSState *env)
{
set_flush_to_zero((env->active_fpu.fcr31 & (1 << FCR31_FS)) != 0,
&env->active_fpu.fp_status);
}
static inline void restore_snan_bit_mode(CPUMIPSState *env)
{
bool nan2008 = env->active_fpu.fcr31 & (1 << FCR31_NAN2008);
/*
* With nan2008, SNaNs are silenced in the usual way.
* Before that, SNaNs are not silenced; default nans are produced.
*/
set_snan_bit_is_one(!nan2008, &env->active_fpu.fp_status);
set_default_nan_mode(!nan2008, &env->active_fpu.fp_status);
}
static inline void restore_fp_status(CPUMIPSState *env)
{
restore_rounding_mode(env);
restore_flush_mode(env);
restore_snan_bit_mode(env);
}
static inline void fp_reset(CPUMIPSState *env)
{
restore_fp_status(env);
/*
* According to MIPS specifications, if one of the two operands is
* a sNaN, a new qNaN has to be generated. This is done in
* floatXX_silence_nan(). For qNaN inputs the specifications
* says: "When possible, this QNaN result is one of the operand QNaN
* values." In practice it seems that most implementations choose
* the first operand if both operands are qNaN. In short this gives
* the following rules:
* 1. A if it is signaling
* 2. B if it is signaling
* 3. A (quiet)
* 4. B (quiet)
* A signaling NaN is always silenced before returning it.
*/
set_float_2nan_prop_rule(float_2nan_prop_s_ab,
&env->active_fpu.fp_status);
}
/* MSA */
enum CPUMIPSMSADataFormat {
DF_BYTE = 0,
DF_HALF,
DF_WORD,
DF_DOUBLE
};
static inline void restore_msa_fp_status(CPUMIPSState *env)
{
float_status *status = &env->active_tc.msa_fp_status;
int rounding_mode = (env->active_tc.msacsr & MSACSR_RM_MASK) >> MSACSR_RM;
bool flush_to_zero = (env->active_tc.msacsr & MSACSR_FS_MASK) != 0;
set_float_rounding_mode(ieee_rm[rounding_mode], status);
set_flush_to_zero(flush_to_zero, status);
set_flush_inputs_to_zero(flush_to_zero, status);
}
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