6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2024-12-26 09:29:45 +00:00
Code Issues Projects Releases Wiki Activity

Corrects ASL overflow flag.

Browse Source
This commit is contained in:
Thomas Harte 2019-07-01 19:46:58 -04:00
parent ebb6313eef
commit 726e07ed5b
1 changed files with 35 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
Processors/68000/Implementation/68000Implementation.hpp
View File

@ -1572,9 +1572,12 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
/*
Shifts and rotates.
*/
#define set_neg_zero_overflow(v, m) \
#define set_neg_zero(v, m) \
zero_result_ = decltype(zero_result_)(v); \
negative_flag_ = zero_result_ & decltype(negative_flag_)(m); \
negative_flag_ = zero_result_ & decltype(negative_flag_)(m);
#define set_neg_zero_overflow(v, m) \
set_neg_zero(v, m); \
overflow_flag_ = (decltype(zero_result_)(value) ^ zero_result_) & decltype(overflow_flag_)(m);
#define decode_shift_count() \
@ -1585,18 +1588,24 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
#define set_flags_w(t) set_flags(active_program_->destination->halves.low.full, 0x8000, t)
#define set_flags_l(t) set_flags(active_program_->destination->full, 0x80000000, t)
#define lsl(destination, size) {\
#define asl(destination, size) {\
decode_shift_count(); \
const auto value = destination; \
\
if(!shift_count) { \
carry_flag_ = 0; \
carry_flag_ = overflow_flag_ = 0; \
} else { \
destination = (shift_count < size) ? decltype(destination)(value << shift_count) : 0; \
extend_flag_ = carry_flag_ = decltype(carry_flag_)(value) & decltype(carry_flag_)( (1u << (size - 1)) >> (shift_count - 1) ); \
\
if(shift_count >= size) overflow_flag_ = value && (value != ((1 << size) - 1)); \
else { \
const auto mask = decltype(destination)((0xffffffff << (size - shift_count)) & ((1 << size) - 1)); \
overflow_flag_ = mask & value && ((mask & value) != mask); \
} \
} \
\
set_neg_zero_overflow(destination, 1 << (size - 1)); \
set_neg_zero(destination, 1 << (size - 1)); \
}
case Operation::ASLm: {
@ -1605,9 +1614,9 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
extend_flag_ = carry_flag_ = value & 0x8000;
set_neg_zero_overflow(active_program_->destination->halves.low.full, 0x8000);
} break;
case Operation::ASLb: lsl(active_program_->destination->halves.low.halves.low, 8); break;
case Operation::ASLw: lsl(active_program_->destination->halves.low.full, 16); break;
case Operation::ASLl: lsl(active_program_->destination->full, 32); break;
case Operation::ASLb: asl(active_program_->destination->halves.low.halves.low, 8); break;
case Operation::ASLw: asl(active_program_->destination->halves.low.full, 16); break;
case Operation::ASLl: asl(active_program_->destination->full, 32); break;
@ -1645,8 +1654,7 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
#undef set_neg_zero_overflow
#define set_neg_zero_overflow(v, m) \
zero_result_ = decltype(zero_result_)(v); \
negative_flag_ = zero_result_ & decltype(zero_result_)(m); \
set_neg_zero(v, m); \
overflow_flag_ = 0;
#undef set_flags
@ -1656,6 +1664,20 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
overflow_flag_ = 0; \
carry_flag_ = value & (t);
#define lsl(destination, size) {\
decode_shift_count(); \
const auto value = destination; \
\
if(!shift_count) { \
carry_flag_ = 0; \
} else { \
destination = (shift_count < size) ? decltype(destination)(value << shift_count) : 0; \
extend_flag_ = carry_flag_ = decltype(carry_flag_)(value) & decltype(carry_flag_)( (1u << (size - 1)) >> (shift_count - 1) ); \
} \
\
set_neg_zero_overflow(destination, 1 << (size - 1)); \
}
case Operation::LSLm: {
const auto value = active_program_->destination->halves.low.full;
active_program_->destination->halves.low.full = uint16_t(value << 1);
@ -1813,6 +1835,7 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
#undef asr
#undef lsr
#undef lsl
#undef asl
#undef set_flags
#undef decode_shift_count
@ -1820,6 +1843,8 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
#undef set_flags_w
#undef set_flags_l
#undef set_neg_zero_overflow
#undef set_net_zero
/*
RTE and RTR share an implementation.
*/