Introduce support for the proposed new (fast-track) Zaamo and Zalrsc extensions [1] which represent the AMO and LR/SC subsets of the A extension.
The motivation for the subsets being available separately is that certain classes of CPUs may choose to only implement a subset for architectural convenience. Since this extension is not frozen these are advertised by "x-zaamo" and "x-zalrsc" options. Beyond adding the extension infrastructure the only changes required are to allow the atomic instructions under either A or the appropriate subset extension. To ensure compatibility enabling the A instruction does not enable these two extensions - future hardware may choose to advertise support for A and both these extensions for maximum software support. This patch is based off riscv-to-apply.next due to conflicts with existing patches. Cheers, Rob [1] - https://github.com/riscv/riscv-zaamo-zalrsc Rob Bradford (2): target/riscv: Add Zaamo and Zalrsc extensions target/riscv: Check 'A' and split extensions for atomic instructions target/riscv/cpu.c | 5 +++ target/riscv/cpu_cfg.h | 2 + target/riscv/insn_trans/trans_rva.c.inc | 56 +++++++++++++++---------- 3 files changed, 41 insertions(+), 22 deletions(-) -- 2.43.0
