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tms9900: More cycle fine-tuning. (nw)

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This commit is contained in:
Michael Zapf 2013-11-30 16:56:40 +00:00
parent ccfd126105
commit d762aef09f
1 changed files with 15 additions and 5 deletions
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20
src/emu/cpu/tms9900/tms9900.c
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@ -703,10 +703,12 @@ MICROPROGRAM(shift_mp)
{
ALU_SHIFT,
MEMORY_READ,
ALU_SHIFT,
MEMORY_READ,
ALU_SHIFT, // 2 cycles if count != 0, else 4
MEMORY_READ, // skipped if count != 0
ALU_SHIFT, // skipped if count != 0 (4 cycles)
ALU_SHIFT,
MEMORY_WRITE,
ALU_NOP,
END
};
@ -2455,6 +2457,7 @@ void tms99xx_device::alu_shift()
{
case 0:
m_address = WP + ((IR & 0x000f)<<1);
pulse_clock(2);
break;
case 1:
// we have the value of the register in m_current_value
@ -2466,15 +2469,23 @@ void tms99xx_device::alu_shift()
if (m_current_value != 0)
{
// skip the next read operation
MPC++;
// skip the next read and ALU operation
MPC = MPC+2;
m_state++;
}
else
{
if (TRACE_ALU) logerror("tms99xx: Shift operation gets count from R0\n");
pulse_clock(2);
}
pulse_clock(2);
break;
case 2:
// after READ
pulse_clock(2);
pulse_clock(2);
break;
case 3:
count = m_current_value & 0x000f; // from the instruction or from R0
if (count==0) count = 16;
@ -2517,7 +2528,6 @@ void tms99xx_device::alu_shift()
break;
}
m_state++;
pulse_clock(2);
}
void tms99xx_device::alu_ai_ori()