diff options
Diffstat (limited to 'arch/x86_64/src/cpu/registers.cpp')
| -rw-r--r-- | arch/x86_64/src/cpu/registers.cpp | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/arch/x86_64/src/cpu/registers.cpp b/arch/x86_64/src/cpu/registers.cpp new file mode 100644 index 0000000..7ade98d --- /dev/null +++ b/arch/x86_64/src/cpu/registers.cpp @@ -0,0 +1,64 @@ +#include "x86_64/cpu/registers.hpp" + +#include <type_traits> + +namespace teachos::x86_64::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; + } + 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::x86_64::cpu |