An instruction for x86 processors. HLT halts the processor until the RESET line is activated or an interrupt or NMI is received. It takes two cycles on an 8088, two on a 186, two on a 286, five on a 386, four on a 486, and four on a 586.

When the processor isn't doing a lot of number crunching, it's often waiting for user input or an i/o request to complete. Halting the processor effectively puts it into a suspended mode, consuming less power and therefore giving off less heat. In use it often decreases heat by 10 degrees centigrade.

Modern operating systems like Linux or Windows NT execute the HLT instruction in an idle priority thread.Windows 98 was supposed to have this feature but it was pulled out last minute.

Log in or register to write something here or to contact authors.