Merge pull request #7 from iximeow/predicate-illegals

Expand the list of unpredicatable instructions

2 files changed, 74 insertions, 19 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 6315bdd..36a892e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -33,11 +33,11 @@ impl Default for Opcode {
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[allow(non_camel_case_types)]
 pub enum Opcode {
-    // TODO: what kind of no-op/undefined are these exactly
-    Purple,
-    Cyan,
-    Brown,
-    White,
+    // Undefined opcode regions come from manual page 3:299.
+    Purple, // Reserved if PR[qp] = 1
+    Cyan,   // Reserved if PR[qp] = 1
+    Brown,  // Reserved
+    White,  // Ignored; executes as nop (for hint space).
 
     Addp4,
     Adds,
@@ -1313,21 +1313,31 @@ impl yaxpeax_arch::Instruction for InstructionBundle {
             // Rotation size cannot be larger than frame.
             (sor << 3) <= sof &&
             // Local size cannot be larger than frame.
-            sol <= sof &&
-            // Alloc cannot be predicated.
-            insn.predicate() == 0
+            sol <= sof
         };
 
         for insn in &self.instructions {
             match insn.opcode {
-                // B8 family instructions cannot be predicated
-                Opcode::Cover | Opcode::Clrrb | Opcode::Clrrb_pr | Opcode::Rfi | Opcode::Bsw_0 | Opcode::Bsw_1 | Opcode::Epc => {
+                // Table 5-5 lists the "unpredicatable-instructions" instruction class, which is:
+                // - the B2 instruction format for br.cloop, br.ctop, br.cexit
+                Opcode::Br_cloop | Opcode::Br_cexit | Opcode::Br_ctop |
+                // - the B6 and B7 instruction format for brp. Note however that B6 and B7 use the qp section of opcode
+                //   to encode the prediction hint, so these are not included.
+                // - the B8 instruction format for bsw.0, bsw.1, clrrrb, clrrrb.pr, cover, epc, rfi, vmsw.0, vmsw.1
+                Opcode::Cover | Opcode::Clrrb | Opcode::Clrrb_pr | Opcode::Rfi | Opcode::Bsw_0 | Opcode::Bsw_1 | Opcode::Epc |
+                // - the M25 instruction format for flushrs, loadrs
+                Opcode::Flushrs | Opcode::Loadrs |
+                // - the M34 instruction format for alloc
+                Opcode::Alloc |
+                // - and br.ia.
+                Opcode::Br_ia => {
                     if insn.predicate() != 0 {
                         return false;
                     }
                 },
                 // Undefined opcode regions
-                Opcode::Purple | Opcode::Cyan | Opcode::Brown | Opcode::White => {
+                // Because Opcode::White instructions are defined to execute as `nop`, they are well-defined.
+                Opcode::Purple | Opcode::Cyan | Opcode::Brown => {
                     return false;
                 },
                 _ => {},
diff --git a/tests/test.rs b/tests/test.rs
index 38b8060..d24fb90 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -2364,14 +2364,6 @@ fn test_alloc_restrictions() {
     assert_eq!(format!("{}", inst), expected);
     assert!(!inst.well_defined());
 
-    // alloc cannot be predicated.
-    let expected = "[MMI] (p02) alloc r34=ar.pfs,5,5,0; break.m 0x0; break.i 0x0";
-    let data = [0x48, 0x10, 0x15, 0x0a, 0x80, 0x05, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
-    let mut reader = U8Reader::new(&data[..]);
-    let inst = decoder.decode(&mut reader).unwrap();
-    assert_eq!(format!("{}", inst), expected);
-    assert!(!inst.well_defined());
-
     // alloc cannot be in slot 1 of a bundle type without a stop before it.
     let expected = "[MMI] break.m 0x0; alloc r34=ar.pfs,5,5,0; break.i 0x0";
     let data = [0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x2a, 0x14, 0x00, 0x0b, 0x00, 0x00, 0x00, 0x00, 0x00];
@@ -2393,6 +2385,28 @@ fn test_alloc_restrictions() {
 fn test_predication_not_allowed() {
     let decoder = InstDecoder::default();
 
+    // B2 instructions cannot be predicated
+    let expected = "[BBB] (p01) br.cloop.sptk.few $+0x0; break.b 0x0; break.b 0x0";
+    let data = [0x36, 0x28, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
+    let mut reader = U8Reader::new(&data[..]);
+    let inst = decoder.decode(&mut reader).unwrap();
+    assert_eq!(format!("{}", inst), expected);
+    assert!(!inst.well_defined());
+
+    let expected = "[BBB] (p01) br.cexit.sptk.few $+0x0; break.b 0x0; break.b 0x0";
+    let data = [0x36, 0x30, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
+    let mut reader = U8Reader::new(&data[..]);
+    let inst = decoder.decode(&mut reader).unwrap();
+    assert_eq!(format!("{}", inst), expected);
+    assert!(!inst.well_defined());
+
+    let expected = "[BBB] (p01) br.ctop.sptk.few $+0x0; break.b 0x0; break.b 0x0";
+    let data = [0x36, 0x38, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
+    let mut reader = U8Reader::new(&data[..]);
+    let inst = decoder.decode(&mut reader).unwrap();
+    assert_eq!(format!("{}", inst), expected);
+    assert!(!inst.well_defined());
+
     // B8 instructions cannot be predicated
     let expected = "[BBB] (p01) cover; break.b 0x0; break.b 0x0";
     let data = [0x36, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
@@ -2442,4 +2456,35 @@ fn test_predication_not_allowed() {
     let inst = decoder.decode(&mut reader).unwrap();
     assert_eq!(format!("{}", inst), expected);
     assert!(!inst.well_defined());
+
+    // M25 instructions cannot be predicated.
+    let expected = "[MMI] (p01) flushrs; break.m 0x0; break.i 0x0";
+    let data = [0x28, 0x00, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
+    let mut reader = U8Reader::new(&data[..]);
+    let inst = decoder.decode(&mut reader).unwrap();
+    assert_eq!(format!("{}", inst), expected);
+    assert!(!inst.well_defined());
+
+    let expected = "[MMI] (p01) loadrs; break.m 0x0; break.i 0x0";
+    let data = [0x28, 0x00, 0x00, 0x00, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
+    let mut reader = U8Reader::new(&data[..]);
+    let inst = decoder.decode(&mut reader).unwrap();
+    assert_eq!(format!("{}", inst), expected);
+    assert!(!inst.well_defined());
+
+    // alloc cannot be predicated.
+    let expected = "[MMI] (p02) alloc r34=ar.pfs,5,5,0; break.m 0x0; break.i 0x0";
+    let data = [0x48, 0x10, 0x15, 0x0a, 0x80, 0x05, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
+    let mut reader = U8Reader::new(&data[..]);
+    let inst = decoder.decode(&mut reader).unwrap();
+    assert_eq!(format!("{}", inst), expected);
+    assert!(!inst.well_defined());
+
+    // br.ia cannot be predicated.
+    let expected = "[BBB] (p01) br.ia b0,0x0,0x0,0x0; break.b 0x0; break.b 0x0";
+    let data = [0x36, 0x08, 0x00, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
+    let mut reader = U8Reader::new(&data[..]);
+    let inst = decoder.decode(&mut reader).unwrap();
+    assert_eq!(format!("{}", inst), expected);
+    assert!(!inst.well_defined());
 }