6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2024-07-16 22:28:57 +00:00
Code Issues Projects Releases Wiki Activity

Add time calculation for MULU and MULS.

Browse Source
This commit is contained in:
Thomas Harte 2022-05-27 14:41:42 -04:00
parent 7601dab464
commit f599a78cad
1 changed files with 19 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
View File

@ -2565,14 +2565,29 @@ template <bool did_overflow> void ProcessorBase::did_divs(int32_t, int32_t) {
// TODO: calculate cost.
}
template <typename IntT> void ProcessorBase::did_mulu(IntT) {
// TODO: calculate cost.
#define convert_to_bit_count_16(x) \
x = ((x & 0xaaaa) >> 1) + (x & 0x5555); \
x = ((x & 0xcccc) >> 2) + (x & 0x3333); \
x = ((x & 0xf0f0) >> 4) + (x & 0x0f0f); \
x = ((x & 0xff00) >> 8) + (x & 0x00ff);
template <typename IntT> void ProcessorBase::did_mulu(IntT multiplier) {
// Count number of bits set.
convert_to_bit_count_16(multiplier);
dynamic_instruction_length_ = multiplier;
}
template <typename IntT> void ProcessorBase::did_muls(IntT) {
// TODO: calculate cost.
template <typename IntT> void ProcessorBase::did_muls(IntT multiplier) {
// Count number of transitions from 0 to 1 or from 1 to 0 — i.e. the
// number of times that a bit is not equal to the one to its right.
// Treat the bit to the right of b0 as 0.
int number_of_pairs = (multiplier ^ (multiplier << 1)) & 0xffff;
convert_to_bit_count_16(number_of_pairs);
dynamic_instruction_length_ = number_of_pairs;
}
#undef convert_to_bit_count_16
void ProcessorBase::did_shift(int bits_shifted) {
dynamic_instruction_length_ = bits_shifted;
}