/* opencoreC - Thread Context Switch */
.global switch_to

.section .text
/*
 * void switch_to(uint64_t **prev_rsp_ptr, uint64_t *next_rsp);
 * RDI = pointer to current thread's stored RSP
 * RSI = target thread's RSP
 */
switch_to:
    /* Push callee-saved registers of outgoing thread */
    push rbp
    push rbx
    push r12
    push r13
    push r14
    push r15

    /* Save current stack pointer */
    mov [rdi], rsp

    /* Load target stack pointer */
    mov rsp, rsi

    /* Pop callee-saved registers of incoming thread */
    pop r15
    pop r14
    pop r13
    pop r12
    pop rbx
    pop rbp

    ret