From 314d3eff66f41f39191aaca2e5f6e3dc81480c1b Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 19 Oct 2022 14:01:36 +0200 Subject: [PATCH] target/i386: introduce function to set rounding mode from FPCW or MXCSR bits MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit VROUND, FSTCW and STMXCSR all have to perform the same conversion from x86 rounding modes to softfloat constants. Since the ISA is consistent on the meaning of the two-bit rounding modes, extract the common code into a wrapper for set_float_rounding_mode. Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Richard Henderson Signed-off-by: Paolo Bonzini --- target/i386/ops_sse.h | 60 +++--------------------------------- target/i386/tcg/fpu_helper.c | 60 +++++++++++++----------------------- 2 files changed, 25 insertions(+), 95 deletions(-) diff --git a/target/i386/ops_sse.h b/target/i386/ops_sse.h index d35fc15c65..0799712f6e 100644 --- a/target/i386/ops_sse.h +++ b/target/i386/ops_sse.h @@ -1684,20 +1684,7 @@ void glue(helper_roundps, SUFFIX)(CPUX86State *env, Reg *d, Reg *s, prev_rounding_mode = env->sse_status.float_rounding_mode; if (!(mode & (1 << 2))) { - switch (mode & 3) { - case 0: - set_float_rounding_mode(float_round_nearest_even, &env->sse_status); - break; - case 1: - set_float_rounding_mode(float_round_down, &env->sse_status); - break; - case 2: - set_float_rounding_mode(float_round_up, &env->sse_status); - break; - case 3: - set_float_rounding_mode(float_round_to_zero, &env->sse_status); - break; - } + set_x86_rounding_mode(mode & 3, &env->sse_status); } for (i = 0; i < 2 << SHIFT; i++) { @@ -1721,20 +1708,7 @@ void glue(helper_roundpd, SUFFIX)(CPUX86State *env, Reg *d, Reg *s, prev_rounding_mode = env->sse_status.float_rounding_mode; if (!(mode & (1 << 2))) { - switch (mode & 3) { - case 0: - set_float_rounding_mode(float_round_nearest_even, &env->sse_status); - break; - case 1: - set_float_rounding_mode(float_round_down, &env->sse_status); - break; - case 2: - set_float_rounding_mode(float_round_up, &env->sse_status); - break; - case 3: - set_float_rounding_mode(float_round_to_zero, &env->sse_status); - break; - } + set_x86_rounding_mode(mode & 3, &env->sse_status); } for (i = 0; i < 1 << SHIFT; i++) { @@ -1759,20 +1733,7 @@ void glue(helper_roundss, SUFFIX)(CPUX86State *env, Reg *d, Reg *v, Reg *s, prev_rounding_mode = env->sse_status.float_rounding_mode; if (!(mode & (1 << 2))) { - switch (mode & 3) { - case 0: - set_float_rounding_mode(float_round_nearest_even, &env->sse_status); - break; - case 1: - set_float_rounding_mode(float_round_down, &env->sse_status); - break; - case 2: - set_float_rounding_mode(float_round_up, &env->sse_status); - break; - case 3: - set_float_rounding_mode(float_round_to_zero, &env->sse_status); - break; - } + set_x86_rounding_mode(mode & 3, &env->sse_status); } d->ZMM_S(0) = float32_round_to_int(s->ZMM_S(0), &env->sse_status); @@ -1797,20 +1758,7 @@ void glue(helper_roundsd, SUFFIX)(CPUX86State *env, Reg *d, Reg *v, Reg *s, prev_rounding_mode = env->sse_status.float_rounding_mode; if (!(mode & (1 << 2))) { - switch (mode & 3) { - case 0: - set_float_rounding_mode(float_round_nearest_even, &env->sse_status); - break; - case 1: - set_float_rounding_mode(float_round_down, &env->sse_status); - break; - case 2: - set_float_rounding_mode(float_round_up, &env->sse_status); - break; - case 3: - set_float_rounding_mode(float_round_to_zero, &env->sse_status); - break; - } + set_x86_rounding_mode(mode & 3, &env->sse_status); } d->ZMM_D(0) = float64_round_to_int(s->ZMM_D(0), &env->sse_status); diff --git a/target/i386/tcg/fpu_helper.c b/target/i386/tcg/fpu_helper.c index a6a90a1817..6f3741b635 100644 --- a/target/i386/tcg/fpu_helper.c +++ b/target/i386/tcg/fpu_helper.c @@ -32,7 +32,8 @@ #define ST(n) (env->fpregs[(env->fpstt + (n)) & 7].d) #define ST1 ST(1) -#define FPU_RC_MASK 0xc00 +#define FPU_RC_SHIFT 10 +#define FPU_RC_MASK (3 << FPU_RC_SHIFT) #define FPU_RC_NEAR 0x000 #define FPU_RC_DOWN 0x400 #define FPU_RC_UP 0x800 @@ -685,28 +686,26 @@ uint32_t helper_fnstcw(CPUX86State *env) return env->fpuc; } +static void set_x86_rounding_mode(unsigned mode, float_status *status) +{ + static FloatRoundMode x86_round_mode[4] = { + float_round_nearest_even, + float_round_down, + float_round_up, + float_round_to_zero + }; + assert(mode < ARRAY_SIZE(x86_round_mode)); + set_float_rounding_mode(x86_round_mode[mode], status); +} + void update_fp_status(CPUX86State *env) { - FloatRoundMode rnd_mode; + int rnd_mode; FloatX80RoundPrec rnd_prec; /* set rounding mode */ - switch (env->fpuc & FPU_RC_MASK) { - default: - case FPU_RC_NEAR: - rnd_mode = float_round_nearest_even; - break; - case FPU_RC_DOWN: - rnd_mode = float_round_down; - break; - case FPU_RC_UP: - rnd_mode = float_round_up; - break; - case FPU_RC_CHOP: - rnd_mode = float_round_to_zero; - break; - } - set_float_rounding_mode(rnd_mode, &env->fp_status); + rnd_mode = (env->fpuc & FPU_RC_MASK) >> FPU_RC_SHIFT; + set_x86_rounding_mode(rnd_mode, &env->fp_status); switch ((env->fpuc >> 8) & 3) { case 0: @@ -3038,11 +3037,8 @@ void helper_xsetbv(CPUX86State *env, uint32_t ecx, uint64_t mask) /* XXX: optimize by storing fptt and fptags in the static cpu state */ #define SSE_DAZ 0x0040 -#define SSE_RC_MASK 0x6000 -#define SSE_RC_NEAR 0x0000 -#define SSE_RC_DOWN 0x2000 -#define SSE_RC_UP 0x4000 -#define SSE_RC_CHOP 0x6000 +#define SSE_RC_SHIFT 13 +#define SSE_RC_MASK (3 << SSE_RC_SHIFT) #define SSE_FZ 0x8000 void update_mxcsr_status(CPUX86State *env) @@ -3051,22 +3047,8 @@ void update_mxcsr_status(CPUX86State *env) int rnd_type; /* set rounding mode */ - switch (mxcsr & SSE_RC_MASK) { - default: - case SSE_RC_NEAR: - rnd_type = float_round_nearest_even; - break; - case SSE_RC_DOWN: - rnd_type = float_round_down; - break; - case SSE_RC_UP: - rnd_type = float_round_up; - break; - case SSE_RC_CHOP: - rnd_type = float_round_to_zero; - break; - } - set_float_rounding_mode(rnd_type, &env->sse_status); + rnd_type = (mxcsr & SSE_RC_MASK) >> SSE_RC_SHIFT; + set_x86_rounding_mode(rnd_type, &env->sse_status); /* Set exception flags. */ set_float_exception_flags((mxcsr & FPUS_IE ? float_flag_invalid : 0) |