diff options
| author | Karel Kočí <cynerd@email.cz> | 2017-12-12 20:42:16 +0100 |
|---|---|---|
| committer | Karel Kočí <cynerd@email.cz> | 2017-12-12 20:42:16 +0100 |
| commit | 1972096df3d235d525bcf761ecb460ba952c0ba9 (patch) | |
| tree | 7c8ace4e9805d59858184ba8ce8c507ab9417573 | |
| parent | 7ab428e3e75854749a39128a8bfcbc47b7844f87 (diff) | |
| download | qtmips-1972096df3d235d525bcf761ecb460ba952c0ba9.tar.gz qtmips-1972096df3d235d525bcf761ecb460ba952c0ba9.tar.bz2 qtmips-1972096df3d235d525bcf761ecb460ba952c0ba9.zip | |
Fix immediate alu operation
There should be a sign extension to 32bit when doing immediate
operations.
| -rw-r--r-- | qtmips_machine/core.cpp | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/qtmips_machine/core.cpp b/qtmips_machine/core.cpp index 93b83dd..5f8321d 100644 --- a/qtmips_machine/core.cpp +++ b/qtmips_machine/core.cpp @@ -134,10 +134,14 @@ struct Core::dtExecute Core::execute(struct dtDecode dt) { if (dt.inst.opcode() == 0 && ((dt.inst.funct() == 10 && dt.val_rt != 0) || (dt.inst.funct() == 11 && dt.val_rt == 0))) regwrite = false; + std::uint32_t alu_sec = dt.val_rt; + if (dt.alusrc) + alu_sec = ((dt.inst.immediate() & 0x8000) << 16) | (dt.inst.immediate() & 0x7FFF); // Sign extend to 32bit + return { .regwrite = regwrite, .rwrite = dt.regd ? dt.inst.rd() : dt.inst.rt(), - .alu_val = alu_operate(dt.aluop, dt.val_rs, dt.alusrc ? dt.inst.immediate() : dt.val_rt, dt.inst.shamt(), regs), + .alu_val = alu_operate(dt.aluop, dt.val_rs, alu_sec, dt.inst.shamt(), regs), }; } |