diff options
| author | iximeow <me@iximeow.net> | 2020-12-06 11:37:19 -0800 |
|---|---|---|
| committer | iximeow <me@iximeow.net> | 2020-12-06 11:58:57 -0800 |
| commit | 72109c2385c7b0940072f31fc3bcbeed68006060 (patch) | |
| tree | 0f35249a5672b2369faf67ca501341f6b65bcaf9 /src/armv7/thumb.rs | |
| parent | f483afc2654391962a821ae41f4a50b484ad9bae (diff) | |
fix more incomplete cases, report arm instruction length properly
Diffstat (limited to 'src/armv7/thumb.rs')
| -rw-r--r-- | src/armv7/thumb.rs | 87 |
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, + ]; } } _ => { |