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// This file is part of x86_64-xsave. It is subject to the license terms in the COPYRIGHT file found in the top-level directory of this distribution and at https://raw.githubusercontent.com/lemonrock/x86_64-xsave/master/COPYRIGHT. No part of x86_64-xsave, including this file, may be copied, modified, propagated, or distributed except according to the terms contained in the COPYRIGHT file. // Copyright © 2019 The developers of x86_64-xsave. See the COPYRIGHT file in the top-level directory of this distribution and at https://raw.githubusercontent.com/lemonrock/x86_64-xsave/master/COPYRIGHT. /// See Figure 8-6 in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1, for the layout of the x87 FPU Control Word. #[derive(Default, Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)] #[repr(transparent)] pub struct X87FloatingPointUnitStatusWord(u16); impl X87FloatingPointUnitStatusWord { /// Reads the control word after raising any pending unmasked floating point exceptions. /// /// Uses the non-`AX` register form of the `FSTSW` instruction (ie always writes to memory); see <https://github.com/HJLebbink/asm-dude/wiki/FSTSW_FNSTSW>. #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] #[inline(always)] pub fn save_after_raising_any_pending_unmasked_floating_point_exceptions() -> Self { let mut control_word: u16 = unsafe { uninitialized() }; let control_word_pointer = &mut control_word; unsafe { asm! ( "fstsw $0" : // Output constraints. "=*m"(control_word_pointer) : // Input constraints. : // Clobbers. : // Options. "volatile" ); } Self(control_word) } /// Reads the control word. /// /// Uses the non-`AX` register form of the `FNSTSW` instruction (ie always writes to memory); see <https://github.com/HJLebbink/asm-dude/wiki/FSTSW_FNSTSW>. #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] #[inline(always)] pub fn save() -> Self { let mut control_word: u16 = unsafe { uninitialized() }; let control_word_pointer = &mut control_word; unsafe { asm! ( "fnstsw $0" : // Output constraints. "=*m"(control_word_pointer) : // Input constraints. : // Clobbers. : // Options. "volatile" ); } Self(control_word) } /// Invalid Operation exception flag, `IE`. /// /// One of the 6 exception flags that can be controlled by the status word. /// /// When set (`true`), the corresponding x87 FPU floating-point exception occurred. #[inline(always)] pub fn exception_flag_invalid_operation(self) -> bool { self.0 & 0b0000_0000_0000_0001 != 0 } /// Denormalized Operand exception flag, `DE`. /// /// One of the 6 exception flags that can be controlled by the status word. /// /// When set (`true`), the corresponding x87 FPU floating-point exception occurred. #[inline(always)] pub fn exception_flag_denormalized_operand(self) -> bool { self.0 & 0b0000_0000_0000_0010 != 0 } /// Zero Divide exception flag, `ZE`. /// /// One of the 6 exception flags that can be controlled by the status word. /// /// When set (`true`), the corresponding x87 FPU floating-point exception occurred. #[inline(always)] pub fn exception_flag_zero_divide(self) -> bool { self.0 & 0b0000_0000_0000_0100 != 0 } /// Overflow exception flag, `OE`. /// /// One of the 6 exception flags that can be controlled by the status word. /// /// When set (`true`), the corresponding x87 FPU floating-point exception occurred. #[inline(always)] pub fn exception_flag_overflow(self) -> bool { self.0 & 0b0000_0000_0000_1000 != 0 } /// Underflow exception flag, `UE`. /// /// One of the 6 exception flags that can be controlled by the status word. /// /// When set (`true`), the corresponding x87 FPU floating-point exception occurred. #[inline(always)] pub fn exception_flag_underflow(self) -> bool { self.0 & 0b0000_0000_0001_0000 != 0 } /// Precision exception flag, `EE`. /// /// One of the 6 exception flags that can be controlled by the status word. /// /// When set (`true`), the corresponding x87 FPU floating-point exception occurred. #[inline(always)] pub fn exception_flag_precision(self) -> bool { self.0 & 0b0000_0000_0010_0000 != 0 } /// Stack Fault exception flag, `SF`. /// /// The stack fault flag indicates that stack overflow or stack underflow has occurred with data in the x87 FPU data register stack. /// The x87 FPU explicitly sets the `SF` flag when it detects a stack overflow or underflow condition, but it does not explicitly clear the flag when it detects an invalid-arithmetic-operand condition. /// When this flag is set, the condition code flag `C1` indicates the nature of the fault: overflow (`C1 = 1`) and underflow (`C1 = 0`). /// /// The `SF` flag is a “sticky” flag, meaning that after it is set, the processor does not clear it until it is explicitly instructed to do so (for example, by an `FINIT`/`FNINIT`, `FCLEX`/`FNCLEX`, or `FSAVE`/`FNSAVE` instruction). #[inline(always)] pub fn stack_fault(self) -> bool { self.0 & 0b0000_0000_0100_0000 != 0 } /// Exception Summary Status, `ES`. /// /// When set (`true`), a x87 FPU floating-point exception occurred. #[inline(always)] pub fn exception_summary_status(self) -> bool { self.0 & 0b0000_0000_1000_0000 != 0 } /// Condition Code `C0`. /// /// See Table 8-1 (Condition Code Interpretation) in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1. #[inline(always)] pub fn condition_code_c0(self) -> bool { self.0 & 0b0000_0001_0000_0000 != 0 } /// Condition Code `C1`. /// /// See Table 8-1 (Condition Code Interpretation) in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1. #[inline(always)] pub fn condition_code_c1(self) -> bool { self.0 & 0b0000_0010_0000_0000 != 0 } /// Condition Code `C2`. /// /// See Table 8-1 (Condition Code Interpretation) in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1. #[inline(always)] pub fn condition_code_c2(self) -> bool { self.0 & 0b0000_0100_0000_0000 != 0 } /// Condition Code `C3`. /// /// See Table 8-1 (Condition Code Interpretation) in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1. #[inline(always)] pub fn condition_code_c3(self) -> bool { self.0 & 0b0100_0000_0000_0000 != 0 } /// Top of Stack Pointer, `TOP`. /// /// A pointer to the x87 FPU data register that is currently at the top of the x87 FPU register stack. /// /// This pointer is a binary value from 0 to 7 (A 3-bit (`u3`) value). #[inline(always)] pub fn top(self) -> u8 { (self.0 & 0b0011_1000_0000_0000 >> 11) as u8 } /// FPU Busy, `B`, or `B-bit`. /// /// This is for 8087 compatibility only. /// It reflects the contents of the `ES` (`self.exception_summary_status()`) flag. #[inline(always)] pub fn fpu_busy(self) -> bool { self.0 & 0b1000_0000_0000_0000 != 0 } }