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mn1880: Fix ASR carry calculation

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This commit is contained in:
AJR 2021-12-17 07:19:33 -05:00
parent 83458ce300
commit 470258626b
1 changed files with 6 additions and 11 deletions
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17
src/devices/cpu/mn1880/mn1880.cpp
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@ -363,6 +363,7 @@ u8 mn1880_device::cpu_registers::addcz(u8 data1, u8 data2, bool carry, bool hold
return data1;
}
// 4-bit decimal add with carry (without adjust)
u8 mn1880_device::cpu_registers::adddcz(u8 data1, u8 data2, bool carry)
{
if (((data1 & 0x0f) + (data2 & 0x0f) + (carry ? 1 : 0)) >= 0x0a)
@ -391,6 +392,7 @@ u8 mn1880_device::cpu_registers::subcz(u8 data1, u8 data2, bool carry, bool hold
return data1;
}
// 4-bit decimal subtract with carry (without adjust)
u8 mn1880_device::cpu_registers::subdcz(u8 data1, u8 data2, bool carry)
{
if ((data1 & 0x0f) < (data2 & 0x0f) + (carry ? 1 : 0))
@ -439,18 +441,11 @@ u8 mn1880_device::cpu_registers::rorc(u8 data)
u8 mn1880_device::cpu_registers::asrc(u8 data)
{
if (BIT(data, 7))
{
if (!BIT(data, 0))
fs &= 0x7f;
return (data >> 1) | 0x80;
}
if (BIT(data, 0))
fs |= 0x80;
else
{
if (BIT(data, 0))
fs |= 0x80;
return data >> 1;
}
fs &= 0x7f;
return (data >> 1) | (data & 0x80);
}
void mn1880_device::cpu_registers::branch(u16 label)