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#include "x86_64/cpu/registers.hpp"
#include <type_traits>
namespace teachos::cpu::x86_64
{
auto read_control_register(control_register cr) -> uint64_t
{
uint64_t current_value;
switch (cr)
{
case control_register::cr0:
asm volatile("mov %%cr0, %[output]" : [output] "=r"(current_value));
break;
case control_register::cr2:
asm volatile("mov %%cr2, %[output]" : [output] "=r"(current_value));
break;
case control_register::cr3:
asm volatile("mov %%cr3, %[output]" : [output] "=r"(current_value));
break;
case control_register::cr4:
asm volatile("mov %%cr4, %[output]" : [output] "=r"(current_value));
break;
}
return current_value;
}
auto write_control_register(control_register cr, uint64_t new_value) -> void
{
switch (cr)
{
case control_register::cr0:
asm volatile("mov %[input], %%cr0"
: /* no output from call */
: [input] "r"(new_value)
: "memory");
break;
case control_register::cr2:
asm volatile("mov %[input], %%cr2"
: /* no output from call */
: [input] "r"(new_value)
: "memory");
break;
case control_register::cr3:
asm volatile("mov %[input], %%cr3"
: /* no output from call */
: [input] "r"(new_value)
: "memory");
break;
case control_register::cr4:
asm volatile("mov %[input], %%cr4"
: /* no output from call */
: [input] "r"(new_value)
: "memory");
break;
}
}
auto set_cr0_bit(cr0_flags flag) -> void
{
auto const cr0 = read_control_register(control_register::cr0);
write_control_register(control_register::cr0, static_cast<std::underlying_type<cr0_flags>::type>(flag) | cr0);
}
} // namespace teachos::cpu::x86_64
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