Re: [PATCH 2/2] target/riscv: fence: reconcile with specification

2022-09-08 Thread Philipp Tomsich
On Thu, 8 Sept 2022 at 11:25, Alistair Francis wrote: > > On Fri, Aug 12, 2022 at 4:19 PM Philipp Tomsich > wrote: > > > > Happy to lower it back into the decode file. > > However, I initially pulled it up into the trans-function to more > > closely match the ISA specification: there is only one

Re: [PATCH 2/2] target/riscv: fence: reconcile with specification

2022-09-08 Thread Alistair Francis
On Fri, Aug 12, 2022 at 4:19 PM Philipp Tomsich wrote: > > Happy to lower it back into the decode file. > However, I initially pulled it up into the trans-function to more > closely match the ISA specification: there is only one FENCE > instruction with 3 arguments (FM, PRED, and SUCC). > One

Re: [PATCH 2/2] target/riscv: fence: reconcile with specification

2022-08-12 Thread Philipp Tomsich
Happy to lower it back into the decode file. However, I initially pulled it up into the trans-function to more closely match the ISA specification: there is only one FENCE instruction with 3 arguments (FM, PRED, and SUCC). One might argue that the decode table for "RV32I Base Instruction Set" in

Re: [PATCH 2/2] target/riscv: fence: reconcile with specification

2022-08-12 Thread Andrew Jones
On Fri, Aug 12, 2022 at 03:13:04PM +0200, Philipp Tomsich wrote: > Our decoding of fence-instructions is problematic in respect to the > RISC-V ISA specification: > - rs and rd are ignored, but need to be 0 > - fm is ignored > > This change adjusts the decode pattern to enfore rs and rd being 0,

Re: [PATCH 2/2] target/riscv: fence: reconcile with specification

2022-08-12 Thread Peter Maydell
On Fri, 12 Aug 2022 at 14:17, Philipp Tomsich wrote: > > Our decoding of fence-instructions is problematic in respect to the > RISC-V ISA specification: > - rs and rd are ignored, but need to be 0 > - fm is ignored > > This change adjusts the decode pattern to enfore rs and rd being 0, > and