From 9578910d7ee5d149ec9a9c46d86f484dc9868bf1 Mon Sep 17 00:00:00 2001
From: Lofty <dan.ravensloft@gmail.com>
Date: Thu, 12 Aug 2021 16:01:48 +0100
Subject: B8 instructions cannot be predicated

---
 src/lib.rs    | 16 ++++++++++++++++
 tests/test.rs | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 74 insertions(+), 2 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 79a5184..4ae7146 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1323,6 +1323,22 @@ impl yaxpeax_arch::Instruction for InstructionBundle {
             insn.predicate() == 0
         };
 
+        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 => {
+                    if insn.predicate() != 0 {
+                        return false;
+                    }
+                },
+                // Undefined opcode regions
+                Opcode::Purple | Opcode::Cyan | Opcode::Brown | Opcode::White => {
+                    return false;
+                },
+                _ => {},
+            }
+        }
+
         if self.instructions[0].opcode() == Opcode::Alloc && !validate_alloc(&self.instructions[0]) {
             return false;
         }
diff --git a/tests/test.rs b/tests/test.rs
index 3734e20..38b8060 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -1,5 +1,5 @@
 use yaxpeax_ia64::InstDecoder;
-use yaxpeax_arch::{Decoder, U8Reader};
+use yaxpeax_arch::{Decoder, Instruction, U8Reader};
 
 // from elf64-ia64-vms.c
 // 0x0b, 0x78, 0x00, 0x02, 0x00, 0x24, 0x00, 0x41, 0x3c, 0x70, 0x27, 0xc0, 0x01, 0x08, 0x00, 0x84
@@ -33,12 +33,14 @@ fn test_invalid_instruction() {
     let mut reader = U8Reader::new(&data[..]);
     let inst = decoder.decode(&mut reader).unwrap();
     assert_eq!(format!("{}", inst), expected);
+    assert!(!inst.well_defined());
 
     let expected = "[MII] purple.nt3; break.i 0x0; break.i 0x0";
     let data = [0x00, 0x00, 0x00, 0x00, 0x0E, 0x0F, 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());
 }
 #[test]
 fn test_ad_hoc() {
@@ -2336,7 +2338,6 @@ fn test_indirection() {
 // alloc has special restrictions that need to be checked.
 #[test]
 fn test_alloc_restrictions() {
-    use yaxpeax_arch::Instruction;
     let decoder = InstDecoder::default();
 
     // size of frame cannot be greater than 96.
@@ -2387,3 +2388,58 @@ fn test_alloc_restrictions() {
     assert_eq!(format!("{}", inst), expected);
     assert!(inst.well_defined());
 }
+
+#[test]
+fn test_predication_not_allowed() {
+    let decoder = InstDecoder::default();
+
+    // 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];
+    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) clrrb; break.b 0x0; break.b 0x0";
+    let data = [0x36, 0x00, 0x00, 0x00, 0x04, 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 = "[BBB] (p01) clrrb.pr; break.b 0x0; break.b 0x0";
+    let data = [0x36, 0x00, 0x00, 0x00, 0x05, 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 = "[BBB] (p01) rfi; break.b 0x0; break.b 0x0";
+    let data = [0x36, 0x00, 0x00, 0x00, 0x08, 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 = "[BBB] (p01) bsw.0; break.b 0x0; break.b 0x0";
+    let data = [0x36, 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 = "[BBB] (p01) bsw.1; break.b 0x0; break.b 0x0";
+    let data = [0x36, 0x00, 0x00, 0x00, 0x0d, 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 = "[BBB] (p01) epc; break.b 0x0; break.b 0x0";
+    let data = [0x36, 0x00, 0x00, 0x00, 0x10, 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());
+}
-- 
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