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62 lines
1.2 KiB
C++
62 lines
1.2 KiB
C++
#include "cmos.h"
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#include "core_interrupt.h"
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#include "ioport.h"
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namespace CMOS {
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static IOPort address(0x70);
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static IOPort data(0x71);
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namespace NMI {
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static const uint8_t mask = 0x80;
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// Cache NMI to speed things up
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static bool disabled = false;
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void enable() {
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bool status = Core::Interrupt::disable();
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uint8_t value = address.inb();
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value &= ~mask;
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address.outb(value);
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Core::Interrupt::restore(status);
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disabled = false;
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}
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void disable() {
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bool status = Core::Interrupt::disable();
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uint8_t value = address.inb();
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value |= mask;
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address.outb(value);
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Core::Interrupt::restore(status);
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disabled = true;
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}
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bool isEnabled() {
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disabled = (address.inb() & mask) != 0;
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return !disabled;
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}
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} // namespace NMI
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static void setAddress(enum Register reg) {
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uint8_t value = reg;
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// The highest bit controls the Non Maskable Interrupt
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// so we don't want to accidentally change it.
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if (NMI::disabled) {
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value |= NMI::mask;
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} else {
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value &= ~NMI::mask;
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}
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address.outb(value);
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}
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uint8_t read(enum Register reg) {
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setAddress(reg);
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return data.inb();
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}
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void write(enum Register reg, uint8_t value) {
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setAddress(reg);
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data.outb(value);
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}
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} // namespace CMOS
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