From 9ea62f571ce8953dba1d2bad2bdeaf9c3a84b7d7 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 14 Jan 2011 20:39:18 +0100 Subject: [PATCH] target-arm: Fix implementation of VRSQRTS The implementation of the ARM VRSQRTS instruction (which calculates (3 - op1 * op2) / 2) was missing the division operation. It also did not handle the special cases of (0,inf) and (inf,0). Signed-off-by: Peter Maydell Reviewed-by: Aurelien Jarno Signed-off-by: Aurelien Jarno --- target-arm/helper.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/target-arm/helper.c b/target-arm/helper.c index 705b99f9cb..ac47de0cba 100644 --- a/target-arm/helper.c +++ b/target-arm/helper.c @@ -2612,8 +2612,16 @@ float32 HELPER(recps_f32)(float32 a, float32 b, CPUState *env) float32 HELPER(rsqrts_f32)(float32 a, float32 b, CPUState *env) { float_status *s = &env->vfp.fp_status; + float32 two = int32_to_float32(2, s); float32 three = int32_to_float32(3, s); - return float32_sub(three, float32_mul(a, b, s), s); + float32 product; + if ((float32_is_infinity(a) && float32_is_zero_or_denormal(b)) || + (float32_is_infinity(b) && float32_is_zero_or_denormal(a))) { + product = float32_zero; + } else { + product = float32_mul(a, b, s); + } + return float32_div(float32_sub(three, product, s), two, s); } /* NEON helpers. */