6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2024-06-17 21:30:14 +00:00
Code Issues Projects Releases Wiki Activity

Eliminate set_decimal_rotate_flags entirely.

Browse Source
This commit is contained in:
Thomas Harte 2024-01-16 13:59:03 -05:00
parent fe34083ab8
commit cc635fd3ea
1 changed files with 9 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
Processors/Z80/Implementation/Z80Implementation.hpp
View File

@ -88,26 +88,25 @@ template < class T,
/// Sets flags as expected at the end of an 8080-style rotate operation (i.e. RRA, RRCA, RLA or RLCA).
/// Specifically:
/// * N and H are set to 0;
/// * C is set to whatever is supplied as new_carry; and
/// * 5 and 3 are set from the result now stored in A.
/// * C is set to whatever is supplied as new_carry;
/// * 5 and 3 are set from the result now stored in A; and
/// * H and N are reset.
const auto set_rotate_flags = [&](uint8_t new_carry) {
bit53_result_ = a_;
carry_result_ = new_carry;
subtract_flag_ = half_carry_result_ = 0;
half_carry_result_ = subtract_flag_ = 0;
set_did_compute_flags();
};
/// Sets flags as expected at the end of a shift or post-8080-style rotate operation.
/// Sets flags as expected at the end of a decimal rotate, shift or post-8080-style rotate operation.
/// Specifically:
/// * N, Z, 5 and 3 are set according to the value of source;
/// * S, Z, 5 and 3 are set according to the value of source;
/// * P is set according to the parity of the source; and
/// * H and N are reset.
const auto set_shift_flags = [&](uint8_t source) {
sign_result_ = zero_result_ = bit53_result_ = source;
set_parity(source);
half_carry_result_ = 0;
subtract_flag_ = 0;
half_carry_result_ = subtract_flag_ = 0;
set_did_compute_flags();
};
@ -783,19 +782,12 @@ template < class T,
set_shift_flags(source);
} break;
#define set_decimal_rotate_flags() \
subtract_flag_ = 0; \
half_carry_result_ = 0; \
set_parity(a_); \
bit53_result_ = zero_result_ = sign_result_ = a_; \
set_did_compute_flags();
case MicroOp::RRD: {
memptr_.full = hl_.full + 1;
const uint8_t low_nibble = a_ & 0xf;
a_ = (a_ & 0xf0) | (temp8_ & 0xf);
temp8_ = uint8_t((temp8_ >> 4) | (low_nibble << 4));
set_decimal_rotate_flags();
set_shift_flags(a_);
} break;
case MicroOp::RLD: {
@ -803,12 +795,9 @@ template < class T,
const uint8_t low_nibble = a_ & 0xf;
a_ = (a_ & 0xf0) | (temp8_ >> 4);
temp8_ = uint8_t((temp8_ << 4) | low_nibble);
set_decimal_rotate_flags();
set_shift_flags(a_);
} break;
#undef set_decimal_rotate_flags
// MARK: - Interrupt state
case MicroOp::EI: