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authorjam1garner <jam@jam1.re>2023-01-31 00:53:05 -0500
committerjam1garner <jam@jam1.re>2023-01-31 00:57:03 -0500
commitaf8fcdb3d748b130919e60c1d3a6172d27e487cd (patch)
treef3a71b187fb1074bbb6dbf82d0d7c8a40e327ed2 /src
parentefbdb28824acc2a94b5910a13da34866da300d20 (diff)
fix 24-bit branch immediate decoding
Diffstat (limited to 'src')
-rw-r--r--src/armv7.rs14
1 files changed, 10 insertions, 4 deletions
diff --git a/src/armv7.rs b/src/armv7.rs
index c2254a5..276b807 100644
--- a/src/armv7.rs
+++ b/src/armv7.rs
@@ -3815,20 +3815,26 @@ impl Decoder<ARMv7> for InstDecoder {
];
} else if op < 0b110000 {
// 10xxxx
- // the + 1 is to compensate for an architecturally-defined initial offset
inst.opcode = Opcode::B;
+
+ // the + 2 is to compensate for an architecturally-defined initial offset
+ let imm24 = ((((word & 0x00ff_ffff) + 2) << 8) as i32) >> 8;
+
inst.operands = [
- Operand::BranchOffset(((word & 0x00ffff) + 1) as i16 as i32),
+ Operand::BranchOffset(imm24),
Operand::Nothing,
Operand::Nothing,
Operand::Nothing,
];
} else {
// 11xxxx
- // the + 1 is to compensate for an architecturally-defined initial offset
+
+ // the + 2 is to compensate for an architecturally-defined initial offset
+ let imm24 = ((((word & 0x00ff_ffff) + 2) << 8) as i32) >> 8;
+
inst.opcode = Opcode::BL;
inst.operands = [
- Operand::BranchOffset(((word & 0x00ffff) + 1) as i16 as i32),
+ Operand::BranchOffset(imm24),
Operand::Nothing,
Operand::Nothing,
Operand::Nothing,