RISC-V Atomic Extensions

• A = Zaamo + Zalrsc

AMO-Related

• Zaamo - Atomic memory operations - AMO*.W, AMO*.D - https://github.com/riscv/riscv-zaamo-zalrsc/blob/main/zaamo-zalrsc.adoc
• Zabha - AMO for Byte/Halfword - AMO*.B, AMO*.H (requires Zaamo) - https://github.com/riscv/riscv-zabha/blob/main/src/zabha.adoc
• Zacas - Atomic Compare and Swap - AMOCAS.* (requires Zaamo) - https://github.com/riscvarchive/riscv-zacas/blob/main/zacas.adoc

Load/Store Related

• Zalrsc - Load Reserved / Store Conditional - LR, SC - https://github.com/riscv/riscv-zaamo-zalrsc/blob/main/zaamo-zalrsc.adoc
• Zalasr - Load-Acquire / Store-Relase - L*.AQ/AQRL, S*.RL/AQRL - https://github.com/riscv/riscv-zalasr/blob/main/chapter2.adoc

Micro-architectural

• Ztso - Total Store Order - no new instructions, just new orderings for existing instructions.

Profile-related info only.

• Za64rs - Reservation Set Size of Max 64 bytes
• Za128rs - Reservation Set Size of Max 128 bytes

Atomic ABI: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-atomic.adoc