diff options
Diffstat (limited to 'devices/src/pic.rs')
| -rw-r--r-- | devices/src/pic.rs | 20 |
1 files changed, 13 insertions, 7 deletions
diff --git a/devices/src/pic.rs b/devices/src/pic.rs index 9b8235f..c18abef 100644 --- a/devices/src/pic.rs +++ b/devices/src/pic.rs @@ -7,10 +7,10 @@ // modern OSs that use a legacy BIOS. // The PIC is connected to the Local APIC on CPU0. -// Terminology note: The 8259A spec refers to "master" and "slave" PITs; the "slave"s are daisy +// Terminology note: The 8259A spec refers to "master" and "slave" PICs; the "slave"s are daisy // chained to the "master"s. // For the purposes of both using more descriptive terms and avoiding terms with lots of charged -// emotional context, this file refers to them instead as "primary" and "secondary" PITs. +// emotional context, this file refers to them instead as "primary" and "secondary" PICs. use crate::BusDevice; use sys_util::{debug, warn}; @@ -56,9 +56,9 @@ struct PicState { } pub struct Pic { - // TODO(mutexlox): Implement an APIC and add necessary state to the Pic. - - // index 0 (aka PicSelect::Primary) is the primary pic, the rest are secondary. + // Indicates a pending INTR signal to LINT0 of vCPU, checked by vCPU thread. + interrupt_request: bool, + // Index 0 (aka PicSelect::Primary) is the primary pic, the rest are secondary. pics: [PicState; 2], } @@ -175,9 +175,9 @@ impl Pic { // The secondary PIC has IRQs 8-15, so we subtract 8 from the IRQ number to get the bit // that should be masked here. In this case, bits 8 - 8 = 0 and 13 - 8 = 5. secondary_pic.elcr_mask = !((1 << 0) | (1 << 5)); - // TODO(mutexlox): Add logic to initialize APIC interrupt-related fields. Pic { + interrupt_request: false, pics: [primary_pic, secondary_pic], } } @@ -205,8 +205,14 @@ impl Pic { self.get_irq(PicSelect::Primary).is_some() } + /// Determines whether the PIC has fired an interrupt to LAPIC. + pub fn interrupt_requested(&self) -> bool { + self.interrupt_request + } + /// Determines the external interrupt number that the PIC is prepared to inject, if any. pub fn get_external_interrupt(&mut self) -> Option<u8> { + self.interrupt_request = false; let irq_primary = if let Some(irq) = self.get_irq(PicSelect::Primary) { irq } else { @@ -403,7 +409,7 @@ impl Pic { } if self.get_irq(PicSelect::Primary).is_some() { - // TODO(mutexlox): Signal local interrupt on APIC bus. + self.interrupt_request = true; // Note: this does not check if the interrupt is succesfully injected into // the CPU, just whether or not one is fired. true |