fix various armv8 and armv8 panics that should be Err.

in fact the decoder should _never_ panic. included here are tests that
cover the entire 32-bit instruction space and ensure that decoding and
display do not panic. these tests run uncomfortably slowly (1168s to
decode the 4b "instruction" sequences on my desktop), but verify that
panics are no longer an issue.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/armv7/thumb.rs b/src/armv7/thumb.rs
index 8017f01..e721691 100644
--- a/src/armv7/thumb.rs
+++ b/src/armv7/thumb.rs
@@ -2956,6 +2956,9 @@ pub fn decode_into<T: Reader<<ARMv7 as Arch>::Address, <ARMv7 as Arch>::Word>>(d
                                     return Err(DecodeError::InvalidOpcode);
                                 }
 
+                                if op1 == 0 {
+                                    return Err(DecodeError::InvalidOpcode);
+                                }
                                 let opcode_idx = (op1 - 1) * 3 + op2;
 
                                 let rn = instr2[0..4].load::<u8>();