Difference between revisions of "HLT"

From Intellivision Wiki
Jump to: navigation, search
m
Line 7: Line 7:
 
<tr><td>Opcode Range</td><td>$0000</td></tr>
 
<tr><td>Opcode Range</td><td>$0000</td></tr>
 
</table><br/>
 
</table><br/>
The Halt (HLT) instruction halts the cpu.  The cpu performs no further processing after receiving this instruction.  This also means that all further interrupts are ignored as well.<br/><br/>
+
The Halt (HLT) instruction halts the [[CP1610]].  The CPU performs no further processing after receiving this instruction.  This also means that all further masked interrupts are ignored as well until the CPU gets reset.<br/><br/>
 +
Currently, it is unknown whether an unmasked interrupt arriving on the INTR input, or if a pulse on the STPST input will restart a halted CPU.  The existing CP1610 documentation does not say.  On the Intellivision, this is irrelevant as both inputs are tied to fixed values.  HLT is mainly useful for debugging.

Revision as of 21:51, 11 January 2005

Instruction NameHalt
MnemonicHLT
CP1610 Clock CyclesInfinity
InterruptibleNo
Opcode Range$0000

The Halt (HLT) instruction halts the CP1610. The CPU performs no further processing after receiving this instruction. This also means that all further masked interrupts are ignored as well until the CPU gets reset.

Currently, it is unknown whether an unmasked interrupt arriving on the INTR input, or if a pulse on the STPST input will restart a halted CPU. The existing CP1610 documentation does not say. On the Intellivision, this is irrelevant as both inputs are tied to fixed values. HLT is mainly useful for debugging.