t-crest / patmos

Patmos is a time-predictable VLIW processor, and the processor for the T-CREST project
http://patmos.compute.dtu.dk
BSD 2-Clause "Simplified" License
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Inconsistent forwarding #4

Closed jeuneS2 closed 11 years ago

jeuneS2 commented 11 years ago

The test case vliw_test/add (and possibly other test cases) show inconsistent forwarding in the simulator. In the first cycle, r1 is assigned 2 in pipeline 0 and 5 in pipeline 1. r2-r7 are assigned r1+r1 in the subsequent cycles. The result is that r1=5 (result from pipeline 1), r2=r3=4 (apparently forwarded from pipeline 0), and r4=r5=r6=r7=10 (forwarded from pipeline 1 or the register file). This should be fixed such that the value in the register and the forwarded values are consistent.

stefanhepp commented 11 years ago

Fixed it locally, will push soon.. (it's in the read_GPR_EX function in instructions.h).

On 05/10/2013 12:28 AM, jeuneS2 wrote:

The test case vliw_test/add (and possibly other test cases) show inconsistent forwarding in the simulator. In the first cycle, r1 is assigned 2 in pipeline 0 and 5 in pipeline 1. r2-r7 are assigned r1+r1 in the subsequent cycles. The result is that r1=5 (result from pipeline 1), r2=r3=4 (apparently forwarded from pipeline 0), and r4=r5=r6=r7=10 (forwarded from pipeline 1 or the register file). This should be fixed such that the value in the register and the forwarded values are consistent.

— Reply to this email directly or view it on GitHub https://github.com/t-crest/patmos/issues/4.

Stefan Hepp E: hepp@complang.tuwien.ac.at Vienna University of Technology W: www.complang.tuwien.ac.at/hepp Institute of Computer Languages T: +43-1-58801-185181 Austria, 1040 Wien, Argentinierstr.8

stefanhepp commented 11 years ago

Pushed it, r2-r7 = 10 now in the vliw add.s test.