add P-Ext ISA

diff --git a/simple_v_extension.mdwn b/simple_v_extension.mdwn
index 43b1698509117adebbf7e6d953ee1a8afdcb639b..ad8fd3a5d13949a3f17c0b66937f8bb23c51a32a 100644 (file)
--- a/simple_v_extension.mdwn
+++ b/simple_v_extension.mdwn
@@ -557,6 +557,18 @@ translates effectively to:
 * ...
 * RV32 LOAD from addr 0x123B to r3
 
+# P-Ext ISA
+
+| Mnemonic           | 16-bit Instruction        |
+| ------------------ | ------------------------- |
+| ADD16 rt, ra, rb   | add                       |
+| RADD16 rt, ra, rb  | Signed Halving add        |
+| URADD16 rt, ra, rb | Unsigned Halving add      |
+| KADD16 rt, ra, rb  | Signed Saturating add     |
+| UKADD16 rt, ra, rb | Unsigned Saturating add   |
+| SUB16 rt, ra, rb   | sub                       |
+| RSUB16 rt, ra, rb  | Signed Halving sub        |
+
 
 # References