x86 Assembly Language Reference Manual

Operating System Support Instructions

The operating system support instructions provide functionality for process management, performance monitoring, debugging, and other systems tasks.

Table 3–45 Operating System Support Instructions


Solaris Mnemonic	Intel/AMD Mnemonic	Description	Notes
`arpl`	`ARPL`	adjust requested privilege level
`clts`	`CLTS`	clear the task-switched flag
`hlt`	`HLT`	halt processor
`invd`	`INVD`	invalidate cache, no writeback
`invlpg`	`INVLPG`	invalidate TLB entry
`lar`	`LAR`	load access rights	`larq` valid only under `-xarch=amd64`
`lgdt`	`LGDT`	load global descriptor table (GDT) register
`lidt`	`LIDT`	load interrupt descriptor table (IDT) register
`lldt`	`LLDT`	load local descriptor table (LDT) register
`lmsw`	`LMSW`	load machine status word
`lock`	`LOCK`	lock bus
`lsl`	`LSL`	load segment limit	`lslq` valid only under `-xarch=amd64`
`ltr`	`LTR`	load task register
`rdmsr`	`RDMSR`	read model-specific register
`rdpmc`	`RDPMC`	read performance monitoring counters
`rdtsc`	`RDTSC`	read time stamp counter
`rsm`	`RSM`	return from system management mode (SMM)
`sgdt`	`SGDT`	store global descriptor table (GDT) register
`sidt`	`SIDT`	store interrupt descriptor table (IDT) register
`sldt`	`SLDT`	store local descriptor table (LDT) register	`sldtq` valid only under `-xarch=amd64`
`smsw`	`SMSW`	store machine status word	`smswq` valid only under `-xarch=amd64`
`str`	`STR`	store task register	`strq` valid only under `-xarch=amd64`
`sysenter`	`SYSENTER`	fast system call, transfers to a flat protected model kernel at CPL=0
`sysexit`	`SYSEXIT`	fast system call, transfers to a flat protected mode kernal at CPL=3
`verr`	`VERR`	verify segment for reading
`verw`	`VERW`	verify segment for writing
`wbinvd`	`WBINVD`	invalidate cache, with writeback
`wrmsr`	`WRMSR`	write model-specific register