neg
RISC-V neg Pseudo-Instruction Details
Assembler pseudo-instructionneg expands to sub rd, x0, rs. SUB computes zero minus rs, ignores overflow, and writes the low XLEN result bits to rd.
What You Write
neg rd, rs
Typical Real Expansion
sub rd, x0, rs
What This Pseudo Instruction Is Saving You From Writing
A SUB spelling with its first source operand fixed to x0.
How To Read The Expansion
Step 1
sub rd, x0, rs
Step 2
SUB computes x0 minus rs.
Assembly Forms And Real Instructions
The expansion above identifies the SUB ISA semantics that apply.
Official References And Reading Order
This page treats pseudo-instructions as assembler-level aliases or macros: first read what real instructions they expand to, then use the official ISA manual for the behavior of those real instructions. ABI, relocation, and linker-relaxation details follow the psABI document.
Pitfalls / Common Confusions
SUB ignores overflow and writes the low XLEN result bits to rd.
FAQ
What is the official neg expansion?
sub rd, x0, rs