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Start added more .net compatibility methods

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Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon 2019-11-03 09:23:28 +00:00
parent 6d90ea6237
commit 20ebbd4048
3 changed files with 7 additions and 5 deletions
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6
Z80/src/Z80.cpp
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@ -436,7 +436,7 @@ void EightBit::Z80::bit(const int n, const uint8_t operand) {
ASSUME(n <= 7);
setFlag(F(), HC);
clearFlag(F(), NF);
const auto discarded = operand & (1 << n);
const auto discarded = operand & Chip::bit(n);
adjustSZ<Z80>(F(), discarded);
clearFlag(F(), PF, discarded);
}
@ -444,13 +444,13 @@ void EightBit::Z80::bit(const int n, const uint8_t operand) {
uint8_t EightBit::Z80::res(const int n, const uint8_t operand) {
ASSUME(n >= 0);
ASSUME(n <= 7);
return operand & ~(1 << n);
return operand & ~Chip::bit(n);
}
uint8_t EightBit::Z80::set(const int n, const uint8_t operand) {
ASSUME(n >= 0);
ASSUME(n <= 7);
return operand | (1 << n);
return operand | Chip::bit(n);
}
void EightBit::Z80::neg() {

2
inc/Chip.h
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@ -45,6 +45,8 @@ namespace EightBit {
Mask16 = Bit16 - 1
};
static constexpr uint8_t bit(const int which) noexcept { return 1 << which; }
static void clearFlag(uint8_t& f, const int flag) noexcept { f &= ~flag; }
static void setFlag(uint8_t& f, const int flag) noexcept { f |= flag; }

4
src/Processor.cpp
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@ -53,8 +53,8 @@ int EightBit::Processor::execute(const uint8_t value) {
// http://graphics.stanford.edu/~seander/bithacks.html#FixedSignExtend
int8_t EightBit::Processor::signExtend(const int b, uint8_t x) {
const uint8_t m = 1 << (b - 1); // mask can be pre-computed if b is fixed
x = x & ((1 << b) - 1); // (Skip this if bits in x above position b are already zero.)
const uint8_t m = bit(b - 1); // mask can be pre-computed if b is fixed
x = x & (bit(b) - 1); // (Skip this if bits in x above position b are already zero.)
const auto result = (x ^ m) - m;
return result;
}