Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS MANUAL VOLUME 1 REV 2.3 Manual page 947

cover
cover — Cover Stack Frame
cover
Format:
A new stack frame of zero size is allocated which does not include any registers from
Description:
the previous frame (as though all output registers in the previous frame had been
locals). The register rename base registers are reset. If interruption collection is
disabled (PSR.ic is zero), then the old value of the Current Frame Marker (CFM) is
copied to the Interruption Function State register (IFS), and IFS.v is set to one.
A cover instruction must be the last instruction in an instruction group; otherwise,
operation is undefined.
This instruction cannot be predicated.
Operation:
if (!followed_by_stop())
undefined_behavior();
if (PSR.cpl == 0 && PSR.vm == 1)
virtualization_fault();
alat_frame_update(CFM.sof, 0);
rse_preserve_frame(CFM.sof);
if (PSR.ic == 0) {
CR[IFS].ifm = CFM;
CR[IFS].v = 1;
}
CFM.sof = 0;
CFM.sol = 0;
CFM.sor = 0;
CFM.rrb.gr = 0;
CFM.rrb.fr = 0;
CFM.rrb.pr = 0;
Virtualization fault
Interruptions:
3:48
B8
Volume 3: Instruction Reference