Calling Conventions for RISC-V 64-bit

• sp contains the stack pointer,
• fp (s0) contains the frame pointer,
• ra contains the return address,
• a0 to a7 are used to pass the first 8 arguments to a subroutine.
• a0 to a1 are used to subroutine return values.

Prologue

1. push the value of ra onto the stack,
2. push the value of fp onto the stack, then
3. read the current value of sp into fp.

addi  sp, sp, -16
sd    s0, 0(sp)
sd    ra, 8(sp)
addi  s0, sp, 0

Epilogue

addi  sp, s0, 0
ld    ra, 8(sp)
ld    s0, 0(sp)
addi  sp, sp, 16
ret