dcmpu

Decimal Compare Unordered

dcmpu BF, FRA, FRB

Compares two DFP operands and sets the CR field to indicate the result.

Details

The dcmpu instruction compares the DFP operand in FRA[p] with the DFP operand in FRB[p]. The result of the compare is placed into CR field BF and the FPCC.

Pseudocode Operation

if (FRA[p] < FRB[p]) then
    BF <- FL
else if (FRA[p] > FRB[p]) then
    BF <- FG
else if (FRA[p] = FRB[p]) then
    BF <- FE
else
    BF <- FU

Programming Note

The dcmpu instruction is used to compare two decimal floating-point numbers. It sets the condition register field BF based on the comparison result, which can be less than (FL), greater than (FG), equal to (FE), or unordered (FU) if either operand is NaN. Ensure that both operands are properly aligned and valid DFP values to avoid undefined behavior.

Example

dcmpu cr0, f2, f3

Encoding

Binary Layout
63
0
BF
6
FRA
11
FRB
16
0
21
0
26
0
30
0
31
 
Format X-form
Opcode 0xEC000504
Extension Decimal Floating-Point
Registers Altered CR, FPSCR

Operands

  • BF
    CR Field
  • FRA
    Src A
  • FRB
    Src B