From c2874f05ab0f92bbcc4c5129dbec14157af32c56 Mon Sep 17 00:00:00 2001 From: iximeow Date: Sun, 6 Dec 2020 02:07:02 -0800 Subject: numerous one-off mis-specializations, most of ld/prefetch hints --- src/armv7.rs | 6 + src/armv7/thumb.rs | 563 +++++++++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 553 insertions(+), 16 deletions(-) diff --git a/src/armv7.rs b/src/armv7.rs index bba3510..aa7aa03 100644 --- a/src/armv7.rs +++ b/src/armv7.rs @@ -463,6 +463,8 @@ impl > Colorize { write!(f, "bfi") }, Opcode::BFC => { write!(f, "bfc") }, Opcode::DBG => { write!(f, "dbg") }, + Opcode::PLD => { write!(f, "pld") }, + Opcode::PLI => { write!(f, "pli") }, } } } @@ -825,6 +829,8 @@ pub enum Opcode { BFI, BFC, DBG, + PLD, + PLI, } static DATA_PROCESSING_OPCODES: [Opcode; 16] = [ diff --git a/src/armv7/thumb.rs b/src/armv7/thumb.rs index bf492df..c78842d 100644 --- a/src/armv7/thumb.rs +++ b/src/armv7/thumb.rs @@ -137,7 +137,7 @@ pub fn decode_into>(decoder: &InstDecoder, inst: &mut I // TODO: double check if op2[2] { // `Load/store dual, load/store exclusive, table branch` (`A6-236`) - let op1op2 = (instr2[5..7].load::() << 2) | instr2[4..6].load::(); + let op1op2 = (instr2[7..9].load::() << 2) | instr2[4..6].load::(); let imm8 = lower2[..8].load::(); let rd = lower2[8..12].load::(); let rt = lower2[12..16].load::(); @@ -436,8 +436,7 @@ pub fn decode_into>(decoder: &InstDecoder, inst: &mut I 0b1110 => { // `STRD (immediate)` (`A8-687`) // v6T2 - // bit 5 (w) == 1 - let w = true; + let w = instr2[5]; let u = instr2[7]; let p = instr2[8]; // `if P == '0' && W == '0' then SEE "Related encodings"` -> this @@ -464,8 +463,7 @@ pub fn decode_into>(decoder: &InstDecoder, inst: &mut I 0b1111 => { // `LDRD (immediate)` (`A8-687`) // v6T2 - // bit 5 (w) == 1 - let w = true; + let w = instr2[5]; let u = instr2[7]; let p = instr2[8]; // `if P == '0' && W == '0' then SEE "Related encodings"` -> this @@ -484,10 +482,10 @@ pub fn decode_into>(decoder: &InstDecoder, inst: &mut I Operand::Reg(Reg::from_u8(rt)), Operand::Reg(Reg::from_u8(rd)), if p { - Operand::RegDerefPostindexOffset(Reg::from_u8(rn), imm8 << 2, u, w) + Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm8 << 2, u, w) } else { // p == 0 and w == 0 is impossible, would be tbb/tbh - Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm8 << 2, u, false) + Operand::RegDerefPostindexOffset(Reg::from_u8(rn), imm8 << 2, u, false) }, Operand::Nothing, ]; @@ -1012,6 +1010,7 @@ pub fn decode_into>(decoder: &InstDecoder, inst: &mut I 0b0001 => { // `BIC` (`A8-338`) // v6T2 + inst.set_w(false); inst.opcode = Opcode::BIC; inst.operands = [ Operand::Reg(Reg::from_u8(rd)), @@ -2178,18 +2177,550 @@ pub fn decode_into>(decoder: &InstDecoder, inst: &mut I // (`A7-273`) } } else { - // load {byte, halfword, word} - let size_bits = (op2[1..].load::()); - if size_bits == 0b00 { - // `Load byte, memory hints` (`A6-239`) - } else if size_bits == 0b01 { - // `Load halfword, memory hints` (`A6-238`) - } else if size_bits == 0b10 { - // `Load word` (`A6-237`) - } else { + // this section is a merger of three tables: + // `A6.3.9 Load byte, memory hints` + // `A6.3.8 Load halfword, memory hints` + // `A6.3.7 Load word` + // reached by the `00xx001`, `00xx011`, `00xx101` rows of table `A6-9`. + + let op2 = lower2[6..12].load::(); + let rt = lower2[12..16].load::(); + let rn = instr2[0..4].load::(); + let op1 = instr2[7..9].load::(); + + // load {byte, halfword, word} in table `A6-9` + let size = instr2[5..7].load::(); + if size == 0b11 { // `UNDEFINED` return Err(DecodeError::Undefined); } + + /* + * trying to reorder tables a6-20, a6-19, and a6-18 to factor out operand + * sizes where possible... + * + * op1 | op2 | rn | rt | size| `see` + * 00 |000000|!=1111|!=1111| 00 |`LDRB (register) A8-423` + * 00 |000000|!=1111|==1111| 00 |`PLD, PLDW (register) A8-529` + * 00 |000000|!=1111|!=1111| 01 |`LDRH (register) A8-447` + * 00 |000000|!=1111|==1111| 01 |`PLD, PLDW (register) A8-529` + * 00 |000000|!=1111|------| 10 |`LDR (register, Thumb) A8-413` + * + * 00 |1100xx|!=1111|!=1111| 00 |`LDRB (immediate, Thumb) A8-417` + * 00 |1100xx|!=1111|==1111| 00 |`PLD, PLDW (immediate) A8-525` + * 00 |1100xx|!=1111|!=1111| 01 |`LDRH (immediate, Thumb) A8-441` + * 00 |1100xx|!=1111|==1111| 01 |`PLD, PLDW (immediate) A8-525` + * 00 |1100xx|!=1111|------| 10 |`LDR (immediate, Thumb) A8-407` + * + * 00 |1110xx|!=1111|------| 00 |`LDRBT A8-425` + * 00 |1110xx|!=1111|------| 01 |`LDRHT A8-449` + * 00 |1110xx|!=1111|------| 10 |`LDRT A8-467` + * + * 00 |1xx1xx|!=1111|------| 00 |`LDRB (immediate, Thumb) A8-417` + * 00 |1xx1xx|!=1111|------| 01 |`LDRH (immediate, Thumb) A8-441` + * 00 |1xx1xx|!=1111|------| 10 |`LDR (immediate, Thumb) A8-407` + * + * 01 |------|!=1111|!=1111| 00 |`LDRB (immediate, Thumb) A8-417` + * 01 |------|!=1111|==1111| 00 |`PLD, PLDW (immediate) A8-525` + * 01 |------|!=1111|!=1111| 01 |`LDRH (immediate, Thumb) A8-441` + * 01 |------|!=1111|==1111| 01 |`PLD, PLDW (immediate) A8-525` + * 01 |------|!=1111|------| 10 |`LDR (immediate, Thumb) A8-407` + * + * 0x |------|==1111|!=1111| 00 |`LDRB (literal) A8-421` + * 0x |------|==1111|==1111| 00 |`PLD (literal) A8-527` + * 0x |------|==1111|!=1111| 01 |`LDRH (literal) A8-445` + * 0x |------|==1111|==1111| 01 |`PLD (literal) A8-527` + * 0x |------|==1111|------| 10 |`LDR (literal) A8-411` + * + * 1x |------|------|------| 10 |`UNDEFINED (cite: A6.3.7)` + * + * 10 |000000|!=1111|!=1111| 00 |`LDRSB (register) A8-455` + * 10 |000000|!=1111|!=1111| 01 |`LDRSH (register) A8-463` + * 10 |000000|!=1111|==1111| 00 |`PLI (register) A8-553` + * 10 |000000|!=1111|==1111| 01 |`Unallocated memory hint (treat as NOP)` + * + * 10 |1100xx|!=1111|!=1111| 00 |`LDRSB (immediate) A8-451` + * 10 |1100xx|!=1111|==1111| 00 |`PLI (immediate, literal) A8-531` + * 10 |1100xx|!=1111|!=1111| 01 |`LDRSH (immediate) A8-459` + * 10 |1100xx|!=1111|==1111| 01 |`Unallocated memory hint (treat as NOP)` + * + * 10 |1110xx|!=1111|------| 00 |`LDRSBT A8-457` + * 10 |1110xx|!=1111|------| 01 |`LDRSHT A8-465` + * + * 10 |1xx1xx|!=1111|------| 00 |`LDRSB (immediate) A8-451` + * 10 |1xx1xx|!=1111|------| 01 |`LDRSH (immediate) A8-459` + * + * 11 |------|!=1111|!=1111| 00 |`LDRSB (immediate) A8-451` + * 11 |------|!=1111|==1111| 00 |`PLI (immediate, literal) A8-531` + * 11 |------|!=1111|!=1111| 01 |`LDRSH (immediate) A8-459` + * 11 |------|!=1111|==1111| 01 |`Unallocated memory hint (treat as NOP)` + * 1x |------|==1111|!=1111| 00 |`LDRSB (literal) A8-453` + * 1x |------|==1111|==1111| 00 |`PLI (immediate, literal) A8-531` + * 1x |------|==1111|!=1111| 01 |`LDRSH (literal) A8-461` + * 1x |------|==1111|==1111| 01 |`Unallocated memory hint (treat as NOP)` + */ + if op1 == 0b00 { + // op1 == bits 7:8 + /* + * op1 | op2 | rn | rt | size| `see` + * 0x |------|==1111|!=1111| 00 |`LDRB (literal) A8-421` + * 0x |------|==1111|==1111| 00 |`PLD (literal) A8-527` + * 0x |------|==1111|!=1111| 01 |`LDRH (literal) A8-445` + * 0x |------|==1111|==1111| 01 |`PLD (literal) A8-527` + * 0x |------|==1111|------| 10 |`LDR (literal) A8-411` + * + * 00 |000000|!=1111|!=1111| 00 |`LDRB (register) A8-423` + * 00 |000000|!=1111|==1111| 00 |`PLD, PLDW (register) A8-529` + * 00 |000000|!=1111|!=1111| 01 |`LDRH (register) A8-447` + * 00 |000000|!=1111|==1111| 01 |`PLD, PLDW (register) A8-529` + * 00 |000000|!=1111|------| 10 |`LDR (register, Thumb) A8-413` + * + * 00 |1100xx|!=1111|!=1111| 00 |`LDRB (immediate, Thumb) A8-417` + * 00 |1100xx|!=1111|==1111| 00 |`PLD, PLDW (immediate) A8-525` + * 00 |1100xx|!=1111|!=1111| 01 |`LDRH (immediate, Thumb) A8-441` + * 00 |1100xx|!=1111|==1111| 01 |`PLD, PLDW (immediate) A8-525` + * 00 |1100xx|!=1111|------| 10 |`LDR (immediate, Thumb) A8-407` + * + * 00 |1110xx|!=1111|------| 00 |`LDRBT A8-425` + * 00 |1110xx|!=1111|------| 01 |`LDRHT A8-449` + * 00 |1110xx|!=1111|------| 10 |`LDRT A8-467` + * + * 00 |1xx1xx|!=1111|------| 00 |`LDRB (immediate, Thumb) A8-417` + * 00 |1xx1xx|!=1111|------| 01 |`LDRH (immediate, Thumb) A8-441` + * 00 |1xx1xx|!=1111|------| 10 |`LDR (immediate, Thumb) A8-407` + */ + if rn == 0b1111 { + // `(literal)` + let opcode = if rt == 0b1111 { + [ + Opcode::PLD, + Opcode::PLD, + Opcode::LDR, + ][size] + } else { + [ + Opcode::LDRB, + Opcode::LDRH, + Opcode::LDR, + ][size] + }; + let u = false; // instr2[7], but known 0 here + let imm12 = lower2[..12].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm12, false, false), // no add, no wback + Operand::Nothing, + Operand::Nothing, + ]; + } else { + if op2 == 0b000000 { + // `(register, Thumb)` + let opcode = if rt == 0b1111 { + [ + Opcode::PLD, + Opcode::PLD, + Opcode::LDR, + ][size] + } else { + [ + Opcode::LDRB, + Opcode::LDRH, + Opcode::LDR, + ][size] + }; + let rm = lower2[0..4].load::(); + let imm2 = lower2[4..6].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + Operand::RegDerefPreindexRegShift( + Reg::from_u8(rn), + RegShift::from_raw( + 0b1000 | // `RegImm` + rm as u16 | + ((0 /* lsl */) << 5)| + ((imm2 as u16) << 7) + ), + true, // add + false, // wback + ), + Operand::Nothing, + Operand::Nothing, + ]; + } else if op2 & 0b111100 == 0b110000 { + // `(immediate, Thumb)` + let opcode = if rt == 0b1111 { + [ + Opcode::PLD, + Opcode::PLD, + Opcode::LDR, + ][size] + } else { + [ + Opcode::LDRB, + Opcode::LDRH, + Opcode::LDR, + ][size] + }; + let w = lower2[8]; + let u = lower2[9]; + let p = lower2[10]; + let imm8 = lower2[..8].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + if p { + Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm8, u, w) + } else { + Operand::RegDerefPostindexOffset(Reg::from_u8(rn), imm8, u, false) + }, + Operand::Nothing, + Operand::Nothing, + ]; + + } else if op2 & 0b111100 == 0b111000 { + // `(immediate, Thumb)` + let opcode = if rt == 0b1111 { + [ + Opcode::PLD, + Opcode::PLD, + Opcode::LDRT, + ][size] + } else { + [ + Opcode::LDRBT, + Opcode::LDRHT, + Opcode::LDRT, + ][size] + }; + let w = lower2[8]; + let u = lower2[9]; + let p = lower2[10]; + let imm8 = lower2[..8].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + if p { + Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm8, u, w) + } else { + Operand::RegDerefPostindexOffset(Reg::from_u8(rn), imm8, u, false) + }, + Operand::Nothing, + Operand::Nothing, + ]; + } else if op2 & 0b100100 == 0b100100 { + // `(immediate, Thumb)` + let opcode = if rt == 0b1111 { + [ + Opcode::PLD, + Opcode::PLD, + Opcode::LDR, + ][size] + } else { + [ + Opcode::LDRB, + Opcode::LDRH, + Opcode::LDR, + ][size] + }; + let w = lower2[8]; + let u = lower2[9]; + let p = lower2[10]; + let imm8 = lower2[..8].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + if p { + Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm8, u, w) + } else { + Operand::RegDerefPostindexOffset(Reg::from_u8(rn), imm8, u, false) + }, + Operand::Nothing, + Operand::Nothing, + ]; + } else { + // op2 =~ 0b1010xx or something? + // nothing to try decoding as for a `decoder.undefined()?`, so + // just error. + return Err(DecodeError::Undefined); + } + } + } else if op1 == 0b01 { + // op1 == bits 7:8 + /* + * op1 | op2 | rn | rt | size| `see` + * 0x |------|==1111|!=1111| 00 |`LDRB (literal) A8-421` + * 0x |------|==1111|==1111| 00 |`PLD (literal) A8-527` + * 0x |------|==1111|!=1111| 01 |`LDRH (literal) A8-445` + * 0x |------|==1111|==1111| 01 |`PLD (literal) A8-527` + * 0x |------|==1111|------| 10 |`LDR (literal) A8-411` + * + * 01 |------|!=1111|!=1111| 00 |`LDRB (immediate, Thumb) A8-417` + * 01 |------|!=1111|==1111| 00 |`PLD, PLDW (immediate) A8-525` + * 01 |------|!=1111|!=1111| 01 |`LDRH (immediate, Thumb) A8-441` + * 01 |------|!=1111|==1111| 01 |`PLD, PLDW (immediate) A8-525` + * 01 |------|!=1111|------| 10 |`LDR (immediate, Thumb) A8-407` + */ + if rn == 0b1111 { + let opcode = if rt == 0b1111 { + [ + Opcode::PLD, + Opcode::PLD, + Opcode::LDR, + ][size] + } else { + [ + Opcode::LDRB, + Opcode::LDRH, + Opcode::LDR, + ][size] + }; + let u = true; // instr2[7], but known 1 here + let imm12 = lower2[..12].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm12, true, false), // add, no wback + Operand::Nothing, + Operand::Nothing, + ]; + } else { + let opcode = if rt == 0b1111 { + [ + Opcode::PLD, + Opcode::PLD, + Opcode::LDR, + ][size] + } else { + [ + Opcode::LDRB, // encoding T2 + Opcode::LDRH, // encoding T2 + Opcode::LDR, // encoding T3 + ][size] + }; + let imm12 = lower2[..12].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm12, true, false), // add, no wback + Operand::Nothing, + Operand::Nothing, + ]; + } + } else if op1 == 0b10 { + // op1 == bits 7:8 + if size == 0b10 { + return Err(DecodeError::Undefined); + } + /* + * op1 | op2 | rn | rt | size| `see` + * 1x |------|------|------| 10 |`UNDEFINED (cite: A6.3.7)` + * 1x |------|==1111|!=1111| 00 |`LDRSB (literal) A8-453` + * 1x |------|==1111|==1111| 00 |`PLI (immediate, literal) A8-531` + * 1x |------|==1111|!=1111| 01 |`LDRSH (literal) A8-461` + * 1x |------|==1111|==1111| 01 |`Unallocated memory hint (treat as NOP)` + * + * 10 |000000|!=1111|!=1111| 00 |`LDRSB (register) A8-455` + * 10 |000000|!=1111|!=1111| 01 |`LDRSH (register) A8-463` + * 10 |000000|!=1111|==1111| 00 |`PLI (register) A8-553` + * 10 |000000|!=1111|==1111| 01 |`Unallocated memory hint (treat as NOP)` + * + * 10 |1100xx|!=1111|!=1111| 00 |`LDRSB (immediate) A8-451` + * 10 |1100xx|!=1111|==1111| 00 |`PLI (immediate, literal) A8-531` + * 10 |1100xx|!=1111|!=1111| 01 |`LDRSH (immediate) A8-459` + * 10 |1100xx|!=1111|==1111| 01 |`Unallocated memory hint (treat as NOP)` + * + * 10 |1110xx|!=1111|------| 00 |`LDRSBT A8-457` + * 10 |1110xx|!=1111|------| 01 |`LDRSHT A8-465` + * + * 10 |1xx1xx|!=1111|------| 00 |`LDRSB (immediate) A8-451` + * 10 |1xx1xx|!=1111|------| 01 |`LDRSH (immediate) A8-459` + */ + if rn == 0b1111 { + // (literal) + let opcode = if rt == 0b1111 { + [ + Opcode::PLI, + Opcode::NOP, + ][size] + } else { + [ + Opcode::LDRSB, + Opcode::LDRSH, + ][size] + }; + let u = false; // instr[7] known false here + let imm12 = lower2[..12].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + Operand::RegDerefPreindexOffset(Reg::from_u8(15), imm12, false, false), // add, no wback + Operand::Nothing, + Operand::Nothing, + ]; + } else { + if op2 == 0b000000 { + let opcode = if rt == 0b1111 { + [ + Opcode::PLI, + Opcode::NOP, + ][size] + } else { + [ + Opcode::LDRSB, // encoding T2 + Opcode::LDRSH, // encoding T2 + ][size] + }; + let rm = lower2[0..4].load::(); + let imm2 = lower2[4..6].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + Operand::RegDerefPreindexRegShift( + Reg::from_u8(rn), + RegShift::from_raw( + 0b1000 | // `RegImm` + rm as u16 | + ((0 /* lsl */) << 5)| + ((imm2 as u16) << 7) + ), + true, // add + false, // wback + ), + Operand::Nothing, + Operand::Nothing, + ]; + } else if op2 & 0b111100 == 0b110000 { + let opcode = if rt == 0b1111 { + [ + Opcode::PLI, + Opcode::NOP, + ][size] + } else { + [ + Opcode::LDRSB, // encoding T2 + Opcode::LDRSH, // encoding T2 + ][size] + }; + let w = lower2[8]; + let u = lower2[9]; + let p = lower2[10]; + let imm8 = lower2[..8].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + if p { + Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm8, u, w) + } else { + Operand::RegDerefPostindexOffset(Reg::from_u8(rn), imm8, u, false) + }, + Operand::Nothing, + Operand::Nothing, + ]; + } else if op2 & 0b111100 == 0b111000 { + let opcode = [ + Opcode::LDRSBT, // encoding T1 + Opcode::LDRSHT, // encoding T1 + ][size]; + let imm8 = lower2[..8].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm8, true, false), // add, no wback + Operand::Nothing, + Operand::Nothing, + ]; + } else if op2 & 0b100100 == 0b100100 { + let opcode = [ + Opcode::LDRSB, // encoding T2 + Opcode::LDRSH, // encoding T2 + ][size]; + let w = lower2[8]; + let u = lower2[9]; + let p = lower2[10]; + let imm8 = lower2[..8].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + if p { + Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm8, u, w) + } else { + Operand::RegDerefPostindexOffset(Reg::from_u8(rn), imm8, u, false) + }, + Operand::Nothing, + Operand::Nothing, + ]; + } else { + // op2 =~ 0b1010xx or something? + // nothing to try decoding as for a `decoder.undefined()?`, so + // just error. + return Err(DecodeError::Undefined); + } + } + } else { + // op1 == bits 7:8 + if size == 0b10 { + return Err(DecodeError::Undefined); + } + // op1 == 0b11 + /* + * 1x |------|------|------| 10 |`UNDEFINED (cite: A6.3.7)` + * 1x |------|==1111|!=1111| 00 |`LDRSB (literal) A8-453` + * 1x |------|==1111|==1111| 00 |`PLI (immediate, literal) A8-531` + * 1x |------|==1111|!=1111| 01 |`LDRSH (literal) A8-461` + * 1x |------|==1111|==1111| 01 |`Unallocated memory hint (treat as NOP)` + * + * 11 |------|!=1111|!=1111| 00 |`LDRSB (immediate) A8-451` + * 11 |------|!=1111|==1111| 00 |`PLI (immediate, literal) A8-531` + * 11 |------|!=1111|!=1111| 01 |`LDRSH (immediate) A8-459` + * 11 |------|!=1111|==1111| 01 |`Unallocated memory hint (treat as NOP)` + */ + if rn == 0b1111 { + // (literal) + let opcode = if rt == 0b1111 { + [ + Opcode::PLI, + Opcode::NOP, + ][size] + } else { + [ + Opcode::LDRSB, + Opcode::LDRSH, + ][size] + }; + let u = true; // instr[7] known true here + let imm12 = lower2[..12].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + Operand::RegDerefPreindexOffset(Reg::from_u8(15), imm12, u, false), // add, no wback + Operand::Nothing, + Operand::Nothing, + ]; + } else { + // (immediate) + let opcode = if rt == 0b1111 { + [ + Opcode::PLI, + Opcode::NOP, + ][size] + } else { + [ + Opcode::LDRSB, // encoding T1 + Opcode::LDRSH, // encoding T1 + ][size] + }; + let imm12 = lower2[..12].load::(); + inst.opcode = opcode; + inst.operands = [ + Operand::Reg(Reg::from_u8(rt)), + Operand::RegDerefPreindexOffset(Reg::from_u8(rn), imm12, true, false), // add, no wback + Operand::Nothing, + Operand::Nothing, + ]; + } + } } } else { if !op2[4] { -- cgit v1.1