#include "./core_ring.h"

#include "./core_interrupt.h"
#include "./gdt.h"

namespace Core {
namespace Ring {
[[gnu::noreturn]]
void switchToUsermode(void *stackpointer, void *kickoff,
					  void *kickoff_parameter) {
	(void)stackpointer;
	(void)kickoff;
	(void)kickoff_parameter;

    // Segment Selectors for Ring 3
    constexpr uint16_t user_cs = 3 << 3 | 3;
    constexpr uint16_t user_ds = 4 << 3 | 3;

    asm volatile ( \
            "mov %[user_data], %%ds \n" \
            "mov %[user_data], %%es \n" \
            "mov %[user_data], %%fs \n" \
            "mov %[user_data], %%gs \n" \
            "pushq %[user_data] \n" \
            "pushq %[user_stack] \n" \
            "pushq %[user_eflags] \n" \
            "pushq %[user_code] \n" \
            "pushq %[user_function] \n" \
            "mov %[user_parameter], %%rdi\n" \
            "iretq \n" \
            : \
            : [user_data] "r"((uint64_t)user_ds), 
              [user_code] "r"((uint64_t)user_cs), 
              [user_stack] "r"((uint64_t)stackpointer), 
              [user_eflags] "r"((uint64_t)1<<9 | 2),  // Interrupt Enable Flag
              [user_function] "r"((uint64_t)kickoff), 
              [user_parameter] "r"((uint64_t)kickoff_parameter)
            \
            : "memory", "rdi"\
            );

	__builtin_unreachable();
}
}  // namespace Ring
}  // namespace Core