target/arm: Convert the VCVT-from-f16 insns to decodetree

Convert the VCVTT, VCVTB instructions that deal with conversion
from half-precision floats to f32 or 64 to decodetree.

Since we're no longer constrained to the old decoder's style
using cpu_F0s and cpu_F0d we can perform a direct 16 bit
load of the right half of the input single-precision register
rather than loading the full 32 bits and then doing a
separate shift or sign-extension.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Peter Maydell 2019-06-11 16:39:51 +01:00
parent 386bba2368
commit b623d803dd
3 changed files with 89 additions and 55 deletions

View file

@ -181,3 +181,9 @@ VCMP_sp ---- 1110 1.11 010 z:1 .... 1010 e:1 1.0 .... \
vd=%vd_sp vm=%vm_sp
VCMP_dp ---- 1110 1.11 010 z:1 .... 1011 e:1 1.0 .... \
vd=%vd_dp vm=%vm_dp
# VCVTT and VCVTB from f16: Vd format depends on size bit; Vm is always vm_sp
VCVT_f32_f16 ---- 1110 1.11 0010 .... 1010 t:1 1.0 .... \
vd=%vd_sp vm=%vm_sp
VCVT_f64_f16 ---- 1110 1.11 0010 .... 1011 t:1 1.0 .... \
vd=%vd_dp vm=%vm_sp