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#include "arch/kernel/cpu/control_register.hpp"
#include "arch/exception_handling/panic.hpp"
#include <type_traits>
namespace teachos::arch::memory::cpu
{
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;
default:
exception_handling::panic("[Control Register] Attempted to read non-existent or reserved control register");
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;
default:
exception_handling::panic("[Control Register] Attempted to write non-existent or reserved control register");
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::arch::memory::cpu
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