diff options
Diffstat (limited to 'src/shared')
| -rw-r--r-- | src/shared/flags.rs | 102 | ||||
| -rw-r--r-- | src/shared/mod.rs | 24 |
2 files changed, 103 insertions, 23 deletions
diff --git a/src/shared/flags.rs b/src/shared/flags.rs new file mode 100644 index 0000000..55dad6d --- /dev/null +++ b/src/shared/flags.rs @@ -0,0 +1,102 @@ +//! Processor state stored in the FLAGS, EFLAGS, or RFLAGS register. + +use shared::PrivilegeLevel; + +/// The RFLAGS register. All variants are backwards compatable so only one +/// bitflags struct needed. +bitflags! { + pub flags Flags: usize { + /// ID Flag (ID) + const FLAGS_ID = 1 << 21, + /// Virtual Interrupt Pending (VIP) + const FLAGS_VIP = 1 << 20, + /// Virtual Interrupt Flag (VIF) + const FLAGS_VIF = 1 << 19, + /// Alignment Check (AC) + const FLAGS_AC = 1 << 18, + /// Virtual-8086 Mode (VM) + const FLAGS_VM = 1 << 17, + /// Resume Flag (RF) + const FLAGS_RF = 1 << 16, + /// Nested Task (NT) + const FLAGS_NT = 1 << 14, + /// I/O Privilege Level (IOPL) 0 + const FLAGS_IOPL0 = 0 << 12, + /// I/O Privilege Level (IOPL) 1 + const FLAGS_IOPL1 = 1 << 12, + /// I/O Privilege Level (IOPL) 2 + const FLAGS_IOPL2 = 2 << 12, + /// I/O Privilege Level (IOPL) 3 + const FLAGS_IOPL3 = 3 << 12, + /// Overflow Flag (OF) + const FLAGS_OF = 1 << 11, + /// Direction Flag (DF) + const FLAGS_DF = 1 << 10, + /// Interrupt Enable Flag (IF) + const FLAGS_IF = 1 << 9, + /// Trap Flag (TF) + const FLAGS_TF = 1 << 8, + /// Sign Flag (SF) + const FLAGS_SF = 1 << 7, + /// Zero Flag (ZF) + const FLAGS_ZF = 1 << 6, + /// Auxiliary Carry Flag (AF) + const FLAGS_AF = 1 << 4, + /// Parity Flag (PF) + const FLAGS_PF = 1 << 2, + /// Bit 1 is always 1. + const FLAGS_A1 = 1 << 1, + /// Carry Flag (CF) + const FLAGS_CF = 1 << 0, + } +} + +impl Flags { + /// Creates a new Flags entry. Ensures bit 1 is set. + pub const fn new() -> Flags { + FLAGS_A1 + } + + /// Creates a new Flags with the given I/O privilege level. + pub const fn from_priv(iopl: PrivilegeLevel) -> Flags { + Flags { bits: (iopl as usize) << 12 } + } +} + +pub fn flags() -> Flags { + + #[cfg(target_arch="x86")] + #[inline(always)] + unsafe fn inner() -> Flags { + let r: usize; + asm!("pushfl; popl $0" : "=r"(r) :: "memory"); + Flags::from_bits_truncate(r) + } + + #[cfg(target_arch="x86_64")] + #[inline(always)] + unsafe fn inner() -> Flags { + let r: usize; + asm!("pushfq; popq $0" : "=r"(r) :: "memory"); + Flags::from_bits_truncate(r) + } + + unsafe { inner() } +} + +pub fn set(val: Flags) { + + #[cfg(target_arch="x86")] + #[inline(always)] + unsafe fn inner(val: Flags) { + asm!("pushl $0; popfl" :: "r"(val.bits()) : "memory" "flags"); + } + + #[cfg(target_arch="x86_64")] + #[inline(always)] + unsafe fn inner(val: Flags) { + asm!("pushq $0; popfq" :: "r"(val.bits()) : "memory" "flags"); + } + + unsafe { inner(val) } +} diff --git a/src/shared/mod.rs b/src/shared/mod.rs index d6190d0..167d7d3 100644 --- a/src/shared/mod.rs +++ b/src/shared/mod.rs @@ -6,32 +6,10 @@ pub mod dtables; pub mod io; pub mod irq; pub mod paging; +pub mod flags; pub mod segmentation; pub mod task; -bitflags! { - pub flags Flags: usize { - const CarryFlag = 1 << 0, - const ParityFlag = 1 << 2, - const AdjustFlag = 1 << 4, - const ZeroFlag = 1 << 6, - const SignFlag = 1 << 7, - const TrapFlag = 1 << 8, - const InterruptFlag = 1 << 9, - const DirectionFlag = 1 << 10, - const OverflowFlag = 1 << 11, - const Iopl1 = 1 << 12, - const Iopl2 = 1 << 13, - const NestedTaskFlag = 1 << 14, - const ResumeFlag = 1 << 16, - const Virtual8086Flag = 1 << 17, - const AlignmentFlag = 1 << 18, - const VirtualInterruptFlag = 1 << 19, - const VirtualInterruptPending = 1 << 20, - const CpuIdFlag = 1 << 21 - } -} - bitflags!( pub flags Features: u64 { const Fpu = 1 << 0, |