add support for experimental CHasSpace instruction

cheri/cheri_insts.sail

@@ -119,6 +119,23 @@ function clause execute (CGetAndAddr(rd, cb, rs)) =
   wGPR(rd) = capVal.address & rs_val;
 }
 
+union clause ast = CHasSpace : (regno, regno, regno)
+function clause execute (CHasSpace (rd, cb, rs)) =
+{
+  checkCP2usable();
+  let cb_val = readCapReg(cb);
+  let cb_cursor = getCapCursor(cb_val);
+  let cb_base = getCapBase(cb_val);
+  let cb_top = getCapTop(cb_val);
+  let rs_val = unsigned(rGPR(rs));
+  if ((cb_cursor + rs_val) <= cb_top) &
+     (cb_cursor < cb_top) &
+     (cb_cursor >= cb_base) then
+    wGPR(rd) = zero_extend(to_bits(1,1))
+  else
+    wGPR(rd) = zeros()
+}
+
 union clause ast = CGetPCC : regno
 function clause execute (CGetPCC(cd)) =
 {
@@ -1567,6 +1584,9 @@ function clause decode (0b010010 @ 0b00000 @ rt : IntRegEnc @ rs : IntRegEnc @
 
 /* Three operand */
 
+/* Capability Inspection */
+function clause decode (0b010010 @ 0b00000 @ rd : IntRegEnc @ cb : CapRegEnc @ rs : IntRegEnc @ 0b100101) = Some(CHasSpace(rd, cb, rs))
+
 /* Capability Modification */
 function clause decode (0b010010 @ 0b00000 @ cd : CapRegEnc @ cs : CapRegEnc @ ct : CapRegEnc @ 0b001011) = Some(CSeal(cd, cs, ct))
 function clause decode (0b010010 @ 0b00000 @ cd : CapRegEnc @ cs : CapRegEnc @ ct : CapRegEnc @ 0b001100) = Some(CUnseal(cd, cs, ct))