add P-Ext ISA

diff --git a/simple_v_extension.mdwn b/simple_v_extension.mdwn
index 6ce5586be92287a3cdc7983f8efaea93660db88d..b3fcc8362c50e63ee239a9830c8baa7af7335151 100644 (file)
--- a/simple_v_extension.mdwn
+++ b/simple_v_extension.mdwn
@@ -584,6 +584,19 @@ translates effectively to:
 | KCRSA16 rt, ra, rb | Signed Saturating Cross Sub & Add   | |
 | UKCRSA16 rt, ra, rb| Unsigned Saturating Cross Sub & Add | |
 
+## 8-bit Arithmetic
+
+| Mnemonic           | 16-bit Instruction        | Simple-V Equivalent |
+| ------------------ | ------------------------- | ------------------- |
+| ADD8 rt, ra, rb    | add                       | RV ADD (bitwidth=8)|
+| RADD8 rt, ra, rb   | Signed Halving add        | |
+| URADD8 rt, ra, rb  | Unsigned Halving add      | |
+| KADD8 rt, ra, rb   | Signed Saturating add     | |
+| UKADD8 rt, ra, rb  | Unsigned Saturating add   | |
+| SUB8 rt, ra, rb    | sub                       | RV SUB (bitwidth=8)|
+| RSUB8 rt, ra, rb   | Signed Halving sub        | |
+| URSUB8 rt, ra, rb  | Unsigned Halving sub      | |
+
 
 
 # References