use a bit of Opcode to indicate rep/repne applicability

this reduces a `slice::contains` to a single bit test, and regroups
prefix printing to deduplicate checks of the `rep` prefix

seemingly this reduces instruction counts by about 1%, cycles by 0.3% or
so.

2 files changed, 30 insertions, 18 deletions

diff --git a/src/long_mode/display.rs b/src/long_mode/display.rs
index b6cca48..71bb1dd 100644
--- a/src/long_mode/display.rs
+++ b/src/long_mode/display.rs
@@ -638,6 +638,13 @@ const MNEMONICS: &[&'static str] = &[
     "not",
     "xadd",
     "xchg",
+    "cmps",
+    "scas",
+    "movs",
+    "lods",
+    "stos",
+    "ins",
+    "outs",
     "invalid",
     "bt",
     "bsf",
@@ -719,17 +726,10 @@ const MNEMONICS: &[&'static str] = &[
     "cwd",
     "cdq",
     "cqo",
-    "lods",
-    "stos",
     "lahf",
     "sahf",
-    "cmps",
-    "scas",
-    "movs",
     "test",
-    "ins",
     "in",
-    "outs",
     "out",
     "imul",
     "jo",
@@ -3613,7 +3613,7 @@ fn contextualize_intel<T: fmt::Write, Y: YaxColors>(instr: &Instruction, colors:
     }
 
     if instr.prefixes.rep_any() {
-        if [Opcode::MOVS, Opcode::CMPS, Opcode::LODS, Opcode::STOS, Opcode::INS, Opcode::OUTS].contains(&instr.opcode) {
+        if instr.opcode.can_rep() {
             if instr.prefixes.rep() {
                 write!(out, "rep ")?;
             } else if instr.prefixes.repnz() {
@@ -3769,7 +3769,7 @@ fn contextualize_c<T: fmt::Write, Y: YaxColors>(instr: &Instruction, colors: &Y,
     }
 
     if instr.prefixes.rep_any() {
-        if [Opcode::MOVS, Opcode::CMPS, Opcode::LODS, Opcode::STOS, Opcode::INS, Opcode::OUTS].contains(&instr.opcode) {
+        if instr.opcode.can_rep() {
             let word_str = match instr.mem_size {
                 1 => "byte",
                 2 => "word",
diff --git a/src/long_mode/mod.rs b/src/long_mode/mod.rs
index 7aab852..41d6f2d 100644
--- a/src/long_mode/mod.rs
+++ b/src/long_mode/mod.rs
@@ -1101,7 +1101,16 @@ pub enum Opcode {
     NOT = 0x1019,
     XADD = 0x101a,
     XCHG = 0x101b,
-    Invalid = 0x1c,
+
+    CMPS = 0x201c,
+    SCAS = 0x201d,
+    MOVS = 0x201e,
+    LODS = 0x201f,
+    STOS = 0x2020,
+    INS = 0x2021,
+    OUTS = 0x2022,
+
+    Invalid = 0x23,
 //    XADD,
     BT,
 //    BTS,
@@ -1186,17 +1195,10 @@ pub enum Opcode {
     CWD,
     CDQ,
     CQO,
-    LODS,
-    STOS,
     LAHF,
     SAHF,
-    CMPS,
-    SCAS,
-    MOVS,
     TEST,
-    INS,
     IN,
-    OUTS,
     OUT,
     IMUL,
     JO,
@@ -4338,6 +4340,16 @@ impl Opcode {
             _ => None,
         }
     }
+
+    #[inline(always)]
+    fn can_lock(&self) -> bool {
+        (*self as u32) & 0x1000 != 0
+    }
+
+    #[inline(always)]
+    fn can_rep(&self) -> bool {
+        (*self as u32) & 0x2000 != 0
+    }
 }
 
 impl Default for Instruction {
@@ -6835,7 +6847,7 @@ fn read_with_annotations<
     self.read_operands(decoder, words, instruction, record, sink)?;
 
     if self.check_lock {
-        if (instruction.opcode as u32) < 0x1000 || !instruction.operands[0].is_memory() {
+        if !instruction.opcode.can_lock() || !instruction.operands[0].is_memory() {
             return Err(DecodeError::InvalidPrefixes);
         }
     }