vcmpgtsq

Vector Compare Greater Than Signed Quadword

vcmpgtsq VRT,VRA,VRB
vcmpgtsq. VRT,VRA,VRB

Compares two signed quadwords and sets the result based on whether the first is greater than the second.

Details

For vcmpgtsq, the contents of VSR[VRA+32] (src1) are compared to the contents of VSR[VRB+32] (src2). If src1 > src2, VSR[VRT+32] is set to all 1s; otherwise, it is set to all 0s. If Rc=1, CR field 6 is updated.

Pseudocode Operation

if MSR.VEC=0 then
    Vector_Unavailable()
all_true ←1
all_false ←1
src1 ←EXTS(VSR[VRA+32])
src2 ←EXTS(VSR[VRB+32])
if src1 > src2 then do
    VSR[VRT+32] ← 0xFFFF_FFFF_FFFF_FFFF_FFFF_FFFF_FFFF_FFFF
    all_false ←0
end else do
    VSR[VRT+32] ← 0x0000_0000_0000_0000_0000_0000_0000_0000
    all_true ←0
end
if Rc=1 then
    CR.field[6] ←all_true || 0b0 || all_false || 0b0

Programming Note

When Rc=1, CR1 is set from the FPSCR[FX, FEX, VX, OX] bits immediately after the operation completes.

Example

vcmpgtsq v1, v2, v3

Encoding

Binary Layout
4
0
VRT
6
VRA
11
VRB
16
Rc
21
 
Format VC-form
Opcode 0x10000387
Extension VMX (AltiVec)
Registers Altered CR6 (if Rc=1)

Operands

  • VRT
    Target Vector Register
  • VRA
    Source Vector Register
  • VRB
    Source Vector Register