target/arm: Implement VFP vp16 VCVT-with-specified-rounding-mode

Implement the fp16 versions of the VFP VCVT instruction forms
which convert between floating point and integer with a specified
rounding mode.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-17-peter.maydell@linaro.org
diff --git a/target/arm/vfp-uncond.decode b/target/arm/vfp-uncond.decode
index ee700e5..b7cd9d1 100644
--- a/target/arm/vfp-uncond.decode
+++ b/target/arm/vfp-uncond.decode
@@ -64,7 +64,9 @@
             vm=%vm_dp vd=%vd_dp dp=1
 
 # VCVT float to int with specified rounding mode; Vd is always single-precision
+VCVT        1111 1110 1.11 11 rm:2 .... 1001 op:1 1.0 .... \
+            vm=%vm_sp vd=%vd_sp sz=1
 VCVT        1111 1110 1.11 11 rm:2 .... 1010 op:1 1.0 .... \
-            vm=%vm_sp vd=%vd_sp dp=0
+            vm=%vm_sp vd=%vd_sp sz=2
 VCVT        1111 1110 1.11 11 rm:2 .... 1011 op:1 1.0 .... \
-            vm=%vm_dp vd=%vd_sp dp=1
+            vm=%vm_dp vd=%vd_sp sz=3