Sprinter/mame
2
0
Fork 0
mirror of https://github.com/holub/mame synced 2025-10-05 08:41:31 +03:00
Code Issues Actions 3 Packages Projects Releases Wiki Activity

Merge pull request #5699 from plaes/tms34020-setcdp

Browse Source 
tms34020: Implement SETCDP opcode
This commit is contained in:
ajrhacker 2019-10-03 21:22:06 -04:00 committed by GitHub
commit d7a453f865
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 30 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
src/devices/cpu/tms34010/34010ops.hxx
View File

@ -2395,7 +2395,36 @@ void tms340x0_device::rpix_b(uint16_t op)
void tms340x0_device::setcdp(uint16_t op)
{
if (!m_is_34020) { unimpl(op); return; }
logerror("020:setcdp\n");
off_t dptch = DPTCH();
// Check whether we're dealing with an even number
if ((dptch & 1) == 0)
{
switch(population_count_32(dptch))
{
// .. only single bit set, pitch is power of two!
case 1:
{
m_convdp = 32 - count_leading_zeros(dptch);
COUNT_CYCLES(4);
return;
}
// .. two bits, we can decompose it to sum of two power of two numbers
case 2:
{
uint8_t first_one = count_leading_zeros(dptch);
uint8_t v1 = 32 - first_one;
uint8_t v2 = 32 - count_leading_zeros(dptch & ~(1 << (first_one - 1)));
m_convdp = v2 | (v1 << 8);
COUNT_CYCLES(6);
return;
}
}
}
// Default to arbitrary number, setting pitch to 0
m_convdp = 0;
COUNT_CYCLES(3);
}
void tms340x0_device::setcmp(uint16_t op)