28.8. Linux calling conventions

Table 3. Summary of Linux calling conventions for several architectures
arch arguments return value callee saved registers

x86_64

rdi, rsi, rdx, rcx, r8, r9, xmm0–7

rax, rdx

rbx, rbp, r12–r15

arm

r0-r3

r0-r3

r4-r11

aarch64

x0-x7

x0-x7

x19-x29