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authoriximeow <me@iximeow.net>2020-12-06 11:37:19 -0800
committeriximeow <me@iximeow.net>2020-12-06 11:58:57 -0800
commit72109c2385c7b0940072f31fc3bcbeed68006060 (patch)
tree0f35249a5672b2369faf67ca501341f6b65bcaf9 /src/armv7/thumb.rs
parentf483afc2654391962a821ae41f4a50b484ad9bae (diff)
fix more incomplete cases, report arm instruction length properly
Diffstat (limited to 'src/armv7/thumb.rs')
-rw-r--r--src/armv7/thumb.rs87
1 files changed, 77 insertions, 10 deletions
diff --git a/src/armv7/thumb.rs b/src/armv7/thumb.rs
index dc2b0e9..6028e7b 100644
--- a/src/armv7/thumb.rs
+++ b/src/armv7/thumb.rs
@@ -99,7 +99,12 @@ fn DecodeImmShift(reg: u8, ty: u8, imm5: u8) -> RegShift {
#[allow(non_snake_case)]
pub fn decode_into<T: IntoIterator<Item=u8>>(decoder: &InstDecoder, inst: &mut Instruction, bytes: T) -> Result<(), DecodeError> {
- inst.set_w(false);
+ // these are cleared in `armv7::InstDecoder::decode_into`.
+ // they must be reset when switching out of thumb decoding or decoding a new thumb instruction,
+ // which that `decode_into` is the entrypoint for in all cases.
+ // inst.set_w(false);
+ // inst.set_wide(false);
+ inst.set_thumb(true);
let mut iter = bytes.into_iter();
let instr: u16 =
((iter.next().ok_or(DecodeError::ExhaustedInput)? as u16) ) |
@@ -113,6 +118,7 @@ pub fn decode_into<T: IntoIterator<Item=u8>>(decoder: &InstDecoder, inst: &mut I
// `A6.1 Thumb instruction set encoding`
if opword >= 0b11101 {
inst.set_w(true);
+ inst.set_wide(true);
// 32b instruction - `A6-228, 32-bit Thumb instruction encoding`
// opword low bits 01, 10, and 11 correspond to `op1` in table `A6-9`
@@ -709,7 +715,7 @@ pub fn decode_into<T: IntoIterator<Item=u8>>(decoder: &InstDecoder, inst: &mut I
let rm = lower2[0..4].load::<u16>();
let shift = RegShift::from_raw(
- 0b00000 | // reg-imm shift. TODO: probably need to change the const
+ 0b00000 | // reg-imm shift
rm as u16 |
(imm2 << 7) | (imm3 << 9) |
tp << 5
@@ -760,31 +766,92 @@ pub fn decode_into<T: IntoIterator<Item=u8>>(decoder: &InstDecoder, inst: &mut I
let tp = (lower >> 4) & 0b11;
let imm2 = (lower >> 6) & 0b11;
let imm3 = (lower >> 12) & 0b111;
+ let imm5 = (imm3 << 2) | imm2;
match tp {
0b00 => {
- if imm2 | imm3 == 0 {
+ if imm5 == 0 {
// `MOV (register, Thumb)` (`A8-487`)
- return Err(DecodeError::Incomplete);
+ // encoding T3
+ inst.set_w(true);
+ let rm = lower2[..4].load::<u8>();
+ let rd = lower2[8..12].load::<u8>();
+ inst.opcode = Opcode::MOV;
+ inst.operands = [
+ Operand::Reg(Reg::from_u8(rd)),
+ Operand::Reg(Reg::from_u8(rm)),
+ Operand::Nothing,
+ Operand::Nothing,
+ ];
} else {
// `LSL (immediate)` (`A8-469`)
- return Err(DecodeError::Incomplete);
+ // encoding T2
+ inst.set_w(true);
+ let rm = lower2[..4].load::<u8>();
+ let rd = lower2[8..12].load::<u8>();
+ inst.opcode = Opcode::LSL;
+ inst.operands = [
+ Operand::Reg(Reg::from_u8(rd)),
+ Operand::Reg(Reg::from_u8(rm)),
+ Operand::Imm12(imm5),
+ Operand::Nothing,
+ ];
}
},
0b01 => {
// `LSR (immediate)` (`A8-473`)
- return Err(DecodeError::Incomplete);
+ // encoding T2
+ inst.set_w(true);
+ let rm = lower2[..4].load::<u8>();
+ let rd = lower2[8..12].load::<u8>();
+ inst.opcode = Opcode::LSR;
+ inst.operands = [
+ Operand::Reg(Reg::from_u8(rd)),
+ Operand::Reg(Reg::from_u8(rm)),
+ Operand::Imm12(imm5),
+ Operand::Nothing,
+ ];
}
0b10 => {
// `ASR (immediate)` (`A8-328`)
- return Err(DecodeError::Incomplete);
+ // encoding T2
+ inst.set_w(true);
+ let rm = lower2[..4].load::<u8>();
+ let rd = lower2[8..12].load::<u8>();
+ inst.opcode = Opcode::ASR;
+ inst.operands = [
+ Operand::Reg(Reg::from_u8(rd)),
+ Operand::Reg(Reg::from_u8(rm)),
+ Operand::Imm12(imm5),
+ Operand::Nothing,
+ ];
}
0b11 => {
- if imm2 | imm3 == 0 {
+ if imm5 == 0 {
// `RRX` (`A8-573`)
- return Err(DecodeError::Incomplete);
+ // encoding T1
+ inst.set_w(false);
+ let rm = lower2[..4].load::<u8>();
+ let rd = lower2[8..12].load::<u8>();
+ inst.opcode = Opcode::RRX;
+ inst.operands = [
+ Operand::Reg(Reg::from_u8(rd)),
+ Operand::Reg(Reg::from_u8(rm)),
+ Operand::Nothing,
+ Operand::Nothing,
+ ];
} else {
// `ROR (immediate)` (`A8-569`)
- return Err(DecodeError::Incomplete);
+ // encoding T1
+ inst.set_w(false);
+ let rm = lower2[..4].load::<u8>();
+ let rd = lower2[8..12].load::<u8>();
+ inst.opcode = Opcode::ASR;
+ inst.operands = [
+ Operand::Reg(Reg::from_u8(rd)),
+ Operand::Reg(Reg::from_u8(rm)),
+ Operand::Imm12(imm5),
+ Operand::Nothing,
+ ];
}
}
_ => {