On 26/12/25 07:42, Li-Hang Lin wrote:
Fix an error in rsqrte_f64() where the sign bit was being
placed incorrectly. Specifically, ensure f64_sign is deposited
into bit 63.
Additionally, update the comments regarding the exponent (exp) bit
width to reflect the correct double-precision specifications.
Fixes: d719cbc7641 ("arm/helper.c: re-factor rsqrte and add rsqrte_f16")
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Signed-off-by: Li-Hang Lin <[email protected]>
---
target/arm/tcg/vfp_helper.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/target/arm/tcg/vfp_helper.c b/target/arm/tcg/vfp_helper.c
index e156e3774a..60188b2c7e 100644
--- a/target/arm/tcg/vfp_helper.c
+++ b/target/arm/tcg/vfp_helper.c
@@ -1078,8 +1078,8 @@ float64 HELPER(rsqrte_f64)(float64 input, float_status *s)
f64_frac = recip_sqrt_estimate(&f64_exp, 3068, f64_frac, false);
- /* result = sign : result_exp<4:0> : estimate<7:0> : Zeros(44) */
- val = deposit64(0, 61, 1, f64_sign);
+ /* result = sign : result_exp<10:0> : estimate<7:0> : Zeros(44) */
+ val = deposit64(0, 63, 1, f64_sign);
val = deposit64(val, 52, 11, f64_exp);
val = deposit64(val, 44, 8, extract64(f64_frac, 52 - 8, 8));
return make_float64(val);
