Sprinter/mame
2
0
Fork 0
mirror of https://github.com/holub/mame synced 2025-07-02 08:39:21 +03:00
Code Issues Actions 1 Packages Projects Releases Wiki Activity

ns32000: implement addp/subp instructions

Browse Source
This commit is contained in:
Patrick Mackinlay 2024-01-11 11:33:25 +07:00
parent 9041258723
commit db37036a12
1 changed files with 72 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
src/devices/cpu/ns32000/ns32000.cpp
View File

@ -2261,9 +2261,43 @@ template <int Width> void ns32000_device<Width>::execute_run()
// SUBPi src,dst
// gen,gen
// read.i,rmw.i
fatalerror("unimplemented: subp (%s)\n", machine().describe_context());
{
mode[0].read_i(size);
mode[1].rmw_i(size);
decode(mode, bytes);
// TODO: tcy 16/18
u32 const src1 = gen_read(mode[0]);
u32 const src2 = gen_read(mode[1]);
// binary coded decimal subtraction with carry
// TODO: CHECK
u32 dst = 0;
bool carry = m_psr & PSR_C;
unsigned const tcy = carry ? 18 : 16;
for (unsigned digit = 0; digit < (size + 1) * 2; digit++)
{
signed sum = BIT(src2, digit * 4, 4) - BIT(src1, digit * 4, 4) - carry;
if (sum < 0)
{
sum = sum + 10;
carry = true;
}
else
carry = false;
dst |= sum << digit * 4;
}
if (carry)
m_psr |= PSR_C;
else
m_psr &= ~PSR_C;
gen_write(mode[1], dst);
tex = mode[0].tea + mode[1].tea + tcy;
}
break;
case 0xc:
// ABSi src,dst
@ -2346,9 +2380,43 @@ template <int Width> void ns32000_device<Width>::execute_run()
// ADDPi src,dst
// gen,gen
// read.i,rmw.i
fatalerror("unimplemented: addp (%s)\n", machine().describe_context());
{
mode[0].read_i(size);
mode[1].rmw_i(size);
decode(mode, bytes);
// TODO: tcy 16/18
u32 const src1 = gen_read(mode[0]);
u32 const src2 = gen_read(mode[1]);
// binary coded decimal addition with carry
// TODO: CHECK
u32 dst = 0;
bool carry = m_psr & PSR_C;
unsigned const tcy = carry ? 18 : 16;
for (unsigned digit = 0; digit < (size + 1) * 2; digit++)
{
unsigned sum = BIT(src1, digit * 4, 4) + BIT(src2, digit * 4, 4) + carry;
if (sum > 9)
{
sum = sum - 10;
carry = true;
}
else
carry = false;
dst |= sum << digit * 4;
}
if (carry)
m_psr |= PSR_C;
else
m_psr &= ~PSR_C;
gen_write(mode[1], dst);
tex = mode[0].tea + mode[1].tea + tcy;
}
break;
}
}