/* opencoreC - Timer Preemptive Interrupt Trampoline (Vector 32 / 0x20) */
.global timer_isr_entry
.extern timer_interrupt_handler

.section .text
timer_isr_entry:
    /* 1. Save all general-purpose registers to form a complete interrupt context frame */
    push rax
    push rbx
    push rcx
    push rdx
    push rsi
    push rdi
    push rbp
    push r8
    push r9
    push r10
    push r11
    push r12
    push r13
    push r14
    push r15

    /* 2. Pass current saved stack pointer in RDI */
    mov rdi, rsp
    call timer_interrupt_handler

    /* 3. Switch stack pointer to returned value (RAX contains next thread's RSP) */
    mov rsp, rax

    /* 4. Restore all general-purpose registers */
    pop r15
    pop r14
    pop r13
    pop r12
    pop r11
    pop r10
    pop r9
    pop r8
    pop rbp
    pop rdi
    pop rsi
    pop rdx
    pop rcx
    pop rbx
    pop rax

    /* 5. Return from interrupt (IRETQ restores RIP, CS, RFLAGS, RSP, SS) */
    iretq