/* opencoreC - Fast Syscall Entry Trampoline (x86_64) */
.global syscall_entry
.extern kernel_syscall_dispatcher

.section .bss
.align 16
user_scratch_rsp:
    .quad 0
kernel_temp_stack:
    .skip 4096
kernel_temp_stack_top:

.section .text
syscall_entry:
    /* Save user stack pointer */
    mov [rip + user_scratch_rsp], rsp
    lea rsp, [rip + kernel_temp_stack_top]

    /* Save user RIP (in RCX) and user RFLAGS (in R11) */
    push rcx
    push r11

    /* Save argument and volatile registers to construct SyscallRegisters */
    push rax
    push rdi
    push rsi
    push rdx
    push r8
    push r9
    push r10

    /* Pass pointer to SyscallRegisters struct in RDI */
    mov rdi, rsp
    call kernel_syscall_dispatcher

    /* Restore registers (rax, rdx, r8 may have return values from dispatcher) */
    pop r10
    pop r9
    pop r8
    pop rdx
    pop rsi
    pop rdi
    pop rax

    /* Restore user RIP and RFLAGS */
    pop r11
    pop rcx

    /* Restore user stack */
    mov rsp, [rip + user_scratch_rsp]

    /* Return to Ring 3 */
    sysretq