Instead, saturate in OpReadRegister, as all uses of OpReadRegisterAndSaturate called OpReadRegister for other registers (and there isn't anything that writes to $ac0.m or $ac1.m without saturation).
There were 3 bugs here:
- The input register for the full register wasn't actually being used; it was read into RCX but RCX wasn't used by Update_SR_Register16_OverS32 (except as a scratch register). The way the DSP LLE recompiler uses registers is in general confusing, so this commit changes a few uses to have a variable for the register being used, to make code a bit more readable. (Default parameter values were also removed so that they needed to be explicitly specified).
- Update_SR_Register16 was doing a 64-bit test, when it should have been doing a 16-bit test. For the most part this doesn't matter due to sign-extension, but it does come up with e.g. `ORI` or `ANDI`.
- Update_SR_Register16_OverS32 did the over s32 check, and then called Update_SR_Register16. Update_SR_Register16 masks $sr with ~SR_CMP_MASK, clearing the over s32 bit. Now the over s32 check is performed after calling Update_SR_Register16 (without masking a second time). No official uCode cares about the over s32 bit.
We don't have anything called $amD, though we do have $acsD. However, these instructions affect flags based on the whole accumulator, so it's better to just use $acD.
For more information, ApplyWriteBackLog, WriteToBackLog, and ZeroWriteBackLog were added in b787f5f8f7 and the explanatory comment was added in fd40513fed, although it did not mention the specific instructions that could trigger this edge case. The statements about which registers can be written by main opcodes and extension opcodes are based on my own checking of all instructions in the manual.
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