[Fix] Decoder uses vtype.vill to decide if instruction is legal - #122
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ilmessere wants to merge 1 commit into
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[Fix] Decoder uses vtype.vill to decide if instruction is legal#122ilmessere wants to merge 1 commit into
ilmessere wants to merge 1 commit into
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This change will make decoder_rsp_o.instr_illegal=1 for instructions that depend on vtype when vtype_q.vill=1 According to the spec, if vill is set, any vector instructions that depends on vtype, must be considered an illegal instructions. (See RISCV unpriv. 30.1.3.4.4. Vector Type Illegal (vill)) In these cases the decoder_rsp_o.instr_illegal remained '0. This causes spatz_req_valid to be set and the request to be sent to the execution units. This means that an illegal instruction may generate a valid request that could result in memory requests or updates of the register file.
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According to the spec, if vill is set, any vector instructions that depends on vtype, must be considered an illegal instructions.
See RISCV unpriv. 30.1.3.4.4. Vector Type Illegal (vill)
In these cases the
decoder_rsp_o.instr_illegalremained'0.This made the
spatz_controllersetspatz_req_valid, and made it send the request the execution units.This means that an illegal instruction could generate a valid spatz request, that could result in memory accesses or updates of the register file.
This change will make
decoder_rsp_o.instr_illegal=1for instructions that depend on vtype whenvtype_q.vill=1.