cpu_reg_cr4_u Union Reference

cr4 register bit fields More...

#include <crx.h>

Public Attributes
struct {
uint8_t   virtual_mode_extensions: 1
	when set enables vme
uint8_t   protected_mode_virtual_ints: 1
	when set eables virtual interrupts at protected mode
uint8_t   timestamp_disable: 1
	disables timestamp
uint8_t   debugging_extensions: 1
	enables debugging
uint8_t   page_size_extensions: 1
	changes page size
uint8_t   physical_address_extension: 1
	enables memory size over 4gib when 32bit
uint8_t   machine_check_enable: 1
	enables machine check
uint8_t   page_global_enable: 1
	enables global pages at page time
uint8_t   performance_monitoring_counter_enable: 1
	enables performance monitoring
uint8_t   os_fx_support: 1
	enables fx (sse)
uint8_t   os_unmasked_exception_support: 1
	enables unmasked simd interrupts
uint8_t   user_mode_instruction_preventation: 1
	disables several instructions at user mode for descriptors
uint8_t   reserved1: 1
	reserved
uint8_t   vmx_enable: 1
	enables virtual machine extensions
uint8_t   smx_enable: 1
	enables safer mode
uint8_t   reserved2: 1
	reserved
uint8_t   fs_gs_base_enable: 1
	enables changing base address of fs and gs registers
uint8_t   process_context_identifier_enable: 1
	enables process context identifier at cr3
uint8_t   os_xsave_eable: 1
	enables xsave instruction
uint8_t   reserved3: 1
	reserved
uint8_t   supervisor_mode_execution_prevention: 1
	enables kernel exection of user space code with rflags
uint8_t   supervisor_mode_access_protection: 1
	enables kernel memory access of user space with rflags
uint8_t   protection_key_enabled: 1
	enables protection key
uint8_t   control_flow_enforcement_technology: 1
	enables control flow
uint8_t   protection_key_enable: 1
	enables protection key for supervisor mode
uint8_t   reserved4: 7
	reserved
uint32_t   reserved5: 32
	reserved
}	fields
	bit field list
uint64_t	bits
	all bits in one 64 bit value

Detailed Description

cr4 register bit fields

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The documentation for this union was generated from the following file:

• includes/cpu/crx.h