mirror of
https://github.com/TomHarte/CLK.git
synced 2024-12-25 18:30:21 +00:00
245 lines
8.6 KiB
Swift
245 lines
8.6 KiB
Swift
//
|
|
// Z80InterruptTests.swift
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 03/06/2017.
|
|
// Copyright © 2017 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
import XCTest
|
|
|
|
class Z80InterruptTests: XCTestCase {
|
|
|
|
private func assertNMI(machine: CSTestMachineZ80) {
|
|
// confirm that the PC is now at 0x66, that the old is on the stack and
|
|
// that IFF1 has migrated to IFF2
|
|
XCTAssertEqual(machine.value(for: .programCounter), 0x66)
|
|
XCTAssertEqual(machine.value(atAddress: 0xffff), 0x01)
|
|
XCTAssertEqual(machine.value(atAddress: 0xfffe), 0x02)
|
|
XCTAssertEqual(machine.value(for: .IFF2), 0)
|
|
}
|
|
|
|
func testNMI() {
|
|
// Per http://www.z80.info/interrup.htm NMI should take 11 cycles to get to 0x66:
|
|
// M1 cycle: 5 T states to do an opcode read and decrement SP
|
|
// M2 cycle: 3 T states write high byte of PC to the stack and decrement SP
|
|
// M3 cycle: 3 T states write the low byte of PC and jump to #0066.
|
|
|
|
let machine = CSTestMachineZ80()
|
|
|
|
// start the PC at 0x0100 and install two NOPs for it
|
|
machine.setValue(0x0100, for: .programCounter)
|
|
machine.setValue(0, for: .IFF1)
|
|
machine.setValue(1, for: .IFF2)
|
|
machine.setValue(0x00, atAddress: 0x0100)
|
|
machine.setValue(0x00, atAddress: 0x0101)
|
|
|
|
// put the stack at the top of memory
|
|
machine.setValue(0, for: .stackPointer)
|
|
|
|
// run for four cycles, and signal an NMI
|
|
machine.runForNumber(ofCycles: 4)
|
|
machine.nmiLine = true
|
|
|
|
// run for four more cycles to get to where the NMI should be recognised
|
|
machine.runForNumber(ofCycles: 4)
|
|
XCTAssertEqual(machine.value(for: .programCounter), 0x0102)
|
|
|
|
// run for eleven more cycles to allow the NMI to begin
|
|
machine.runForNumber(ofCycles: 11)
|
|
|
|
assertNMI(machine: machine)
|
|
}
|
|
|
|
func testHaltNMIWait() {
|
|
let machine = CSTestMachineZ80()
|
|
|
|
// start the PC at 0x0100 and install a NOP and a HALT for it
|
|
machine.setValue(0x0100, for: .programCounter)
|
|
machine.setValue(0, for: .IFF1)
|
|
machine.setValue(1, for: .IFF2)
|
|
machine.setValue(0x00, atAddress: 0x0100)
|
|
machine.setValue(0x76, atAddress: 0x0101)
|
|
|
|
// put the stack at the top of memory
|
|
machine.setValue(0, for: .stackPointer)
|
|
|
|
// run for ten cycles, check that the processor is halted and assert an NMI
|
|
machine.runForNumber(ofCycles: 10)
|
|
XCTAssert(machine.isHalted, "Machine should be halted")
|
|
machine.nmiLine = true
|
|
|
|
// check that the machine ceases believing itsef to be halted after two cycles
|
|
machine.runForNumber(ofCycles: 1)
|
|
XCTAssert(machine.isHalted, "Machine should still be halted")
|
|
machine.runForNumber(ofCycles: 1)
|
|
XCTAssert(!machine.isHalted, "Machine should no longer be halted")
|
|
|
|
// assert wait
|
|
machine.waitLine = true
|
|
|
|
// run for twenty cycles, an arbitrary big number
|
|
machine.runForNumber(ofCycles: 20)
|
|
|
|
// release wait
|
|
machine.waitLine = false
|
|
|
|
// NMI should have run for two cycles, then waited, so now there should be nine cycles left
|
|
machine.runForNumber(ofCycles: 9)
|
|
assertNMI(machine: machine)
|
|
}
|
|
|
|
func testIRQDisabled() {
|
|
let machine = CSTestMachineZ80()
|
|
|
|
// start the PC at 0x0100, interrupts disabled
|
|
machine.setValue(0x0100, for: .programCounter)
|
|
machine.setValue(0, for: .IFF1)
|
|
machine.setValue(0, for: .IFF2)
|
|
|
|
// install six NOPs
|
|
for address: UInt16 in 0x0100 ..< 0x0106 {
|
|
machine.setValue(0x00, atAddress: address)
|
|
}
|
|
|
|
// replace the fourth NOP with an EI
|
|
machine.setValue(0xfb, atAddress: 0x0103)
|
|
|
|
// run for four cycles, signal IRQ and run for 8 more
|
|
machine.runForNumber(ofCycles: 4)
|
|
machine.irqLine = true
|
|
machine.runForNumber(ofCycles: 8)
|
|
|
|
// confirm that the request was ignored
|
|
XCTAssertEqual(machine.value(for: .programCounter), 0x0103)
|
|
|
|
// run for 12 more cycles, hitting the EI and, if no interrupt occured, the two NOPs after it
|
|
machine.runForNumber(ofCycles: 12)
|
|
|
|
// confirm that an interruption occurred, causing the PC not yet to have proceeded beyond 0x0105
|
|
XCTAssertEqual(machine.value(for: .programCounter), 0x0105)
|
|
}
|
|
|
|
func testIRQMode0() {
|
|
// In interrupt mode 0, receipt of an IRQ causes an instruction to be read from the bus and
|
|
// executed, with a two-cycle penalty. The test machine posts 0x21 during an interrupt acknowledge
|
|
// cycle so the instruction that is executed will be LD HL, nnnn
|
|
|
|
let machine = CSTestMachineZ80()
|
|
|
|
// start the PC at 0x0100 and install two NOPs for it and then one copy of 0x83, then
|
|
// something that isn't 0x83, and ensuring interrupts are enabled and in mode 1
|
|
machine.setValue(0x0100, for: .programCounter)
|
|
machine.setValue(1, for: .IFF1)
|
|
machine.setValue(0, for: .IM)
|
|
machine.setValue(0x1010, for: .HL)
|
|
machine.setValue(0x00, atAddress: 0x0100)
|
|
machine.setValue(0x00, atAddress: 0x0101)
|
|
machine.setValue(0x83, atAddress: 0x0102)
|
|
machine.setValue(0x9b, atAddress: 0x0103)
|
|
|
|
// run for four cycles, and signal an IRQ
|
|
machine.runForNumber(ofCycles: 4)
|
|
machine.irqLine = true
|
|
|
|
// run for four more cycles to get to where the IRQ should be recognised
|
|
machine.runForNumber(ofCycles: 4)
|
|
XCTAssertEqual(machine.value(for: .programCounter), 0x0102)
|
|
|
|
// run for twelve more cycles, to complete a LD HL, nnnn with the additional two cycles
|
|
// of cost for it being an IRQ program
|
|
machine.runForNumber(ofCycles: 12)
|
|
|
|
// confirm that the PC is still where it was, but HL is now 0x8383, and interrupts are disabled
|
|
XCTAssertEqual(machine.value(for: .programCounter), 0x0102)
|
|
XCTAssertEqual(machine.value(for: .HL), 0x8383)
|
|
XCTAssertEqual(machine.value(for: .IFF1), 0)
|
|
}
|
|
|
|
func testIRQMode1() {
|
|
// In interrupt mode 1, receipt of an IRQ means that the interrupt flag is disabled,
|
|
// the PC is pushed to the stack and execution resumes at 0x38. This should take
|
|
// 13 cycles total, per http://www.z80.info/interrup.htm
|
|
|
|
let machine = CSTestMachineZ80()
|
|
|
|
// start the PC at 0x0100 and install three NOPs for it, ensuring interrupts are enabled
|
|
// and in mode 1
|
|
machine.setValue(0x0100, for: .programCounter)
|
|
machine.setValue(1, for: .IFF1)
|
|
machine.setValue(1, for: .IM)
|
|
machine.setValue(0x00, atAddress: 0x0100)
|
|
machine.setValue(0x00, atAddress: 0x0101)
|
|
machine.setValue(0x00, atAddress: 0x0102)
|
|
|
|
// put the stack at the top of memory
|
|
machine.setValue(0, for: .stackPointer)
|
|
|
|
// run for four cycles, and signal an IRQ
|
|
machine.runForNumber(ofCycles: 4)
|
|
machine.irqLine = true
|
|
|
|
// run for four more cycles to get to where the IRQ should be recognised
|
|
machine.runForNumber(ofCycles: 4)
|
|
XCTAssertEqual(machine.value(for: .programCounter), 0x0102)
|
|
|
|
// run for twelve cycles and confirm that the IRQ has yet to begin
|
|
machine.runForNumber(ofCycles: 12)
|
|
|
|
XCTAssertNotEqual(machine.value(for: .programCounter), 0x38)
|
|
|
|
// run for one more cycles to allow the IRQ to begin
|
|
machine.runForNumber(ofCycles: 1)
|
|
|
|
// confirm that the PC is now at 0x38, that the old is on the stack and
|
|
// that interrupts are now disabled
|
|
XCTAssertEqual(machine.value(for: .programCounter), 0x38)
|
|
XCTAssertEqual(machine.value(atAddress: 0xffff), 0x01)
|
|
XCTAssertEqual(machine.value(atAddress: 0xfffe), 0x02)
|
|
XCTAssertEqual(machine.value(for: .IFF1), 0)
|
|
}
|
|
|
|
func testIRQMode2() {
|
|
// In interrupt mode 2, the current bus value is combined with the I register to look
|
|
// up a vector from memory; the PC calls that vector. Total cost: 19 cycles.
|
|
|
|
let machine = CSTestMachineZ80()
|
|
|
|
// start the PC at 0x0100 and install two NOPs for it and then one copy of 0x83, then
|
|
// something that isn't 0x83, and ensuring interrupts are enabled and in mode 1
|
|
machine.setValue(0x0100, for: .programCounter)
|
|
machine.setValue(1, for: .IFF1)
|
|
machine.setValue(2, for: .IM)
|
|
machine.setValue(0x00, atAddress: 0x0100)
|
|
machine.setValue(0x00, atAddress: 0x0101)
|
|
|
|
// set I to 0x0200 to establish the location of our vector table, and because the test
|
|
// machine will post a 0x21 in response to the interrupt cycle, at 0x0221 put the
|
|
// arbitrarily-chosen address 0x8049
|
|
machine.setValue(0x02, for: .I)
|
|
machine.setValue(0x49, atAddress: 0x0221)
|
|
machine.setValue(0x80, atAddress: 0x0222)
|
|
|
|
// put the stack at the top of memory
|
|
machine.setValue(0, for: .stackPointer)
|
|
|
|
// run for four cycles, and signal an IRQ
|
|
machine.runForNumber(ofCycles: 4)
|
|
machine.irqLine = true
|
|
|
|
// run for four more cycles to get to where the IRQ should be recognised
|
|
machine.runForNumber(ofCycles: 4)
|
|
XCTAssertEqual(machine.value(for: .programCounter), 0x0102)
|
|
|
|
// run for nineteen more cycles, to complete the interrupt beginning
|
|
machine.runForNumber(ofCycles: 19)
|
|
|
|
// confirm that the PC is now at 0x8049, the old is on the stack, and interrupts
|
|
// are disabled
|
|
XCTAssertEqual(machine.value(for: .programCounter), 0x8049)
|
|
XCTAssertEqual(machine.value(atAddress: 0xffff), 0x01)
|
|
XCTAssertEqual(machine.value(atAddress: 0xfffe), 0x02)
|
|
XCTAssertEqual(machine.value(for: .IFF1), 0)
|
|
}
|
|
}
|