fix some forms of lss/lfs/lgs having incorrectly-small memory sizes

5 files changed, 26 insertions, 8 deletions

diff --git a/CHANGELOG b/CHANGELOG
index ae3baf7..888017b 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -28,6 +28,9 @@
   protected and real modes.
 * fix lfs/lgs/lss loading into dword registers when operating with a short (16-bit segment/offset) pointer.
   in these cases, the offset is loaded into a 16-bit register, not 32-bit. the upper 32 bits are unchanged.
+* fix 32/16-bit unprefixed lfs/lgs/lss reporting too-small memory read.  in both modes
+  these instructions could be decoded as reading only an offset, rather than an offset (into the
+  destination register) and segment (into ss)
 
 testing instruction round-tripping through `masm` found a few bugs, which are also fixed in this release:
 
diff --git a/src/protected_mode/mod.rs b/src/protected_mode/mod.rs
index a3e6a96..6c0e674 100644
--- a/src/protected_mode/mod.rs
+++ b/src/protected_mode/mod.rs
@@ -10599,10 +10599,10 @@ const OPERAND_SIZE_0F_CODES: [OpcodeRecord; 256] = [
 // 0xb0
     OpcodeRecord::new(Interpretation::Instruction(Opcode::CMPXCHG), OperandCode::Eb_Gb),
     OpcodeRecord::new(Interpretation::Instruction(Opcode::CMPXCHG), OperandCode::Ev_Gv),
-    OpcodeRecord::new(Interpretation::Instruction(Opcode::LSS), OperandCode::Gv_M),
+    OpcodeRecord::new(Interpretation::Instruction(Opcode::LSS), OperandCode::INV_Gv_M),
     OpcodeRecord::new(Interpretation::Instruction(Opcode::BTR), OperandCode::Ev_Gv),
-    OpcodeRecord::new(Interpretation::Instruction(Opcode::LFS), OperandCode::Gv_M),
-    OpcodeRecord::new(Interpretation::Instruction(Opcode::LGS), OperandCode::Gv_M),
+    OpcodeRecord::new(Interpretation::Instruction(Opcode::LFS), OperandCode::INV_Gv_M),
+    OpcodeRecord::new(Interpretation::Instruction(Opcode::LGS), OperandCode::INV_Gv_M),
     OpcodeRecord::new(Interpretation::Instruction(Opcode::MOVZX), OperandCode::Gv_Eb),
     OpcodeRecord::new(Interpretation::Instruction(Opcode::MOVZX), OperandCode::Gv_Ew),
     OpcodeRecord::new(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
diff --git a/src/real_mode/mod.rs b/src/real_mode/mod.rs
index ba50394..274d472 100644
--- a/src/real_mode/mod.rs
+++ b/src/real_mode/mod.rs
@@ -10658,10 +10658,10 @@ const OPERAND_SIZE_0F_CODES: [OpcodeRecord; 256] = [
 // 0xb0
     OpcodeRecord::new(Interpretation::Instruction(Opcode::CMPXCHG), OperandCode::Eb_Gb),
     OpcodeRecord::new(Interpretation::Instruction(Opcode::CMPXCHG), OperandCode::Ev_Gv),
-    OpcodeRecord::new(Interpretation::Instruction(Opcode::LSS), OperandCode::Gv_M),
+    OpcodeRecord::new(Interpretation::Instruction(Opcode::LSS), OperandCode::INV_Gv_M),
     OpcodeRecord::new(Interpretation::Instruction(Opcode::BTR), OperandCode::Ev_Gv),
-    OpcodeRecord::new(Interpretation::Instruction(Opcode::LFS), OperandCode::Gv_M),
-    OpcodeRecord::new(Interpretation::Instruction(Opcode::LGS), OperandCode::Gv_M),
+    OpcodeRecord::new(Interpretation::Instruction(Opcode::LFS), OperandCode::INV_Gv_M),
+    OpcodeRecord::new(Interpretation::Instruction(Opcode::LGS), OperandCode::INV_Gv_M),
     OpcodeRecord::new(Interpretation::Instruction(Opcode::MOVZX), OperandCode::Gv_Eb),
     OpcodeRecord::new(Interpretation::Instruction(Opcode::MOVZX), OperandCode::Gv_Ew),
     OpcodeRecord::new(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
diff --git a/test/long_mode/mod.rs b/test/long_mode/mod.rs
index fb38840..de113d3 100644
--- a/test/long_mode/mod.rs
+++ b/test/long_mode/mod.rs
@@ -1893,11 +1893,21 @@ mod system {
     use crate::long_mode::{TestCase, run_test};
 
     const CASES: &'static [TestCase] = &[
+        testcase!(&[0x0f, 0xb2, 0x00], "lss eax, far [rax]"),
+        testcase!(&[0x0f, 0xb4, 0x00], "lfs eax, far [rax]"),
+        testcase!(&[0x0f, 0xb5, 0x00], "lgs eax, far [rax]"),
+        testcase!(&[0x48, 0x0f, 0xb2, 0x00], "lss rax, mword [rax]"),
+        testcase!(&[0x48, 0x0f, 0xb4, 0x00], "lfs rax, mword [rax]"),
+        testcase!(&[0x48, 0x0f, 0xb5, 0x00], "lgs rax, mword [rax]"),
         testcase!(&[0x66, 0x4f, 0x0f, 0xb2, 0x00], "lss r8, mword [r8]"),
         testcase!(&[0x67, 0x4f, 0x0f, 0xb2, 0x00], "lss r8, mword [r8d]"),
         testcase!(&[0x4f, 0x0f, 0xb2, 0x00], "lss r8, mword [r8]"),
+        testcase!(&[0x4f, 0x0f, 0xb4, 0x00], "lfs r8, mword [r8]"),
+        testcase!(&[0x4f, 0x0f, 0xb5, 0x00], "lgs r8, mword [r8]"),
         testcase!(&[0x0f, 0xb2, 0x00], "lss eax, far [rax]"),
         testcase!(&[0x66, 0x0f, 0xb2, 0x00], "lss ax, dword [rax]"),
+        testcase!(&[0x66, 0x0f, 0xb4, 0x00], "lfs ax, dword [rax]"),
+        testcase!(&[0x66, 0x0f, 0xb5, 0x00], "lgs ax, dword [rax]"),
         testcase!(invalid: &[0x45, 0x0f, 0x22, 0xc8]),
         testcase!(invalid: &[0x45, 0x0f, 0x20, 0xc8]),
         testcase!(&[0x40, 0x0f, 0x22, 0xd0], "mov cr2, rax"),
diff --git a/test/protected_mode/mod.rs b/test/protected_mode/mod.rs
index 7fb3b77..2b1cc70 100644
--- a/test/protected_mode/mod.rs
+++ b/test/protected_mode/mod.rs
@@ -1829,12 +1829,17 @@ mod system {
     use crate::protected_mode::{TestCase, run_test};
 
     const CASES: &'static [TestCase] = &[
+        testcase!(&[0x0f, 0xb2, 0x00], "lss eax, far [eax]"),
+        testcase!(&[0x0f, 0xb4, 0x00], "lfs eax, far [eax]"),
+        testcase!(&[0x0f, 0xb5, 0x00], "lgs eax, far [eax]"),
         testcase!(&[0x63, 0xc1], "arpl cx, ax"),
         testcase!(&[0x63, 0x04, 0xba], "arpl word [edx + edi * 4], ax"),
-        testcase!(&[0x66, 0x0f, 0xb2, 0x00], "lss ax, word [eax]"),
+        testcase!(&[0x66, 0x0f, 0xb2, 0x00], "lss ax, dword [eax]"),
+        testcase!(&[0x66, 0x0f, 0xb4, 0x00], "lfs ax, dword [eax]"),
+        testcase!(&[0x66, 0x0f, 0xb5, 0x00], "lgs ax, dword [eax]"),
         testcase!(&[0x67, 0x0f, 0xb2, 0x00], "lss eax, far [bx + si * 1]"),
         testcase!(&[0x0f, 0xb2, 0x00], "lss eax, far [eax]"),
-        testcase!(&[0x66, 0x0f, 0xb2, 0x00], "lss ax, word [eax]"),
+        testcase!(&[0x66, 0x0f, 0xb2, 0x00], "lss ax, dword [eax]"),
         testcase!(invalid: &[0x0f, 0x22, 0xc8]),
         testcase!(invalid: &[0x0f, 0x20, 0xc8]),
         testcase!(&[0x0f, 0x22, 0xd0], "mov cr2, eax"),