[SECTION .text]
[GLOBAL context_switch]
[GLOBAL context_launch]
[GLOBAL fake_systemv_abi]

; context_switch saves the registers in the current context structure
; and populates the registers from the the next context.
align 16
context_switch:
    mov  [rsi +  0],  rbx
    mov  [rsi +  8],  rbp
    mov  [rsi + 16],  r12
    mov  [rsi + 24],  r13
    mov  [rsi + 32],  r14
    mov  [rsi + 40],  r15
    mov  [rsi + 48],  rsp

; context_launch populates the register set from the next context structure.
; It does not save the current registers.
align 16 ; When only one parameter is used for `align`, it will use NOP
context_launch:
    mov  rbx, [rdi +  0] 
    mov  rbp, [rdi +  8] 
    mov  r12, [rdi + 16] 
    mov  r13, [rdi + 24] 
    mov  r14, [rdi + 32] 
    mov  r15, [rdi + 40] 
    mov  rsp, [rdi + 48] 
    ret
; fake_systemv_abi is used to populate the volatile argument registers used by the systemv abi (rdi, rsi, ...)
; with values from the non-volatile registers saved within the thread context (r15, r14, ...)
align 16
fake_systemv_abi:
mov rdi, r15
mov rsi, r14
ret