Intel Itanium 9150M, Manual

Page: 57 / 420

3:48 Volume 3: Instruction Reference
cover
cover — Cover Stack Frame
Format: cover B8
Description:
A new stack frame of zero size is allocated which does not include any registers from
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;
Interruptions:
Virtualization fault