Register Guide
RISC-V fa3 / f13 Register: Floating argument register
f13/fa3 is a floating-point register used by F/D/Q/Zfh instructions for operands and results. Under the hardware floating-point calling convention, fa3 is used for FP arguments.
ABI name: fa3; physical register: f13.
Save rule: Caller.
Read it through its psABI role first, then inspect how each instruction reads or writes it.
Physical Name f13ABI Name fa3Save Rule Caller
Role
Floating argument register
Convention
Caller-saved
Remember This First
The calling convention listed for this entry is: Caller-saved.
psABI Floating-Point Register Reference
ABI register
f13/fa3 is a floating-point register used by F/D/Q/Zfh instructions for operands and results. Under the hardware floating-point calling convention, fa3 is used for FP arguments.
Preserved across calls: Caller
RISC-V psABI floating-point register conventionWhen It Fits Best
- - Use it according to the documented role: Floating argument register.
- - Consult the applicable ISA or ABI specification for concrete read, write, or execution semantics.
When Not To Use It This Way
- - Do not apply the integer temporary-register t* rules to this entry.
- - Do not infer behavior not defined by this page or the applicable specification from the ABI name.
What Happens Around A Call
1
The calling convention listed for this entry is: Caller-saved.
2
The save rule listed for this entry is: Caller.
Read The Documented Role
Examples explain the rule, not a complete program# f13 / fa3
# Floating argument register
# Caller-saved