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With some degree of hit and hope, correct 65C02 results.

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This commit is contained in:
Thomas Harte 2023-08-31 15:28:59 -04:00
parent 39ee75d94a
commit 4d6ffa7a2e
2 changed files with 9 additions and 6 deletions
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4
OSBindings/Mac/Clock SignalTests/BCDTest.swift
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@ -48,10 +48,6 @@ class BCDTest: XCTestCase, CSTestMachineTrapHandler {
testBCD(processor: .processor65C02)
}
// func test6816BCD() {
// testBCD(processor: .processor65816)
// }
private var output: String = ""
func testMachine(_ testMachine: CSTestMachine, didTrapAtAddress address: UInt16) {
let machine6502 = testMachine as! CSTestMachine6502

11
Processors/6502/Implementation/6502Implementation.hpp
View File

@ -298,6 +298,13 @@ template <Personality personality, typename T, bool uses_ready_line> void Proces
// The bottom nibble is adjusted if there was carry into the top nibble;
// this doesn't cause additional carry.
if(!Numeric::carried_in<4>(a_, operand_, result)) {
// 65C02 difference: carry from the calculation below is applied as
// borrow to the nibble above.
if constexpr (is_65c02(personality)) {
if((result & 0xf) < 0x6) {
result -= 0x10;
}
}
result = (result & 0xf0) | ((result + 0x0a) & 0xf);
}
@ -308,7 +315,7 @@ template <Personality personality, typename T, bool uses_ready_line> void Proces
a_ = result;
if(is_65c02(personality)) {
if constexpr (is_65c02(personality)) {
// 65C02 fix: set the N and Z flags based on the final, decimal result.
flags_.set_nz(a_);
read_mem(operand_, address_.full);
@ -351,7 +358,7 @@ template <Personality personality, typename T, bool uses_ready_line> void Proces
a_ = result;
if(is_65c02(personality)) {
if constexpr (is_65c02(personality)) {
// 65C02 fix: N and Z are set correctly based on the final BCD result, at the cost of
// an extra cycle.
flags_.set_nz(a_);