Page 115 - ARM 64 Bit Assembly Language

Data processing and other instructions 101

cneg Conditional Negate,
cset Conditional Set, and
csetm Conditional Set Mask.
Conditional comparison instructions allow PSTATE to be set to either a comparison or an im-
mediate, depending on the flags in PSTATE:

ccmp Conditional Compare,
ccmn Conditional Compare Negative.
The conditional compare and compare negative instructions check the PSTATE flags for the
given condition. If it is true, then it sets the PSTATE flags to the comparison of Rn and either
Rm or <imm5>.Ifitisfalse,itsetsthe PSTATE flags to an immediate four bit value represent-
ing nzcv.

4.2.10.1 Syntax

<op> Rd, Rn, Rm, <cond>
<op2> Rd, Rn, <cond>
<op3> Rd, <cond>
ccmp Rn, Rm|#<imm5>, #<nzcv>, <cond>
ccmn Rn, Rm|#<imm5>, #<nzcv>, <cond>

• <op> is one of csel, csinc, csinv,or csneg.
• <op2> is one of cinc, cinv,or cneg.
• <op3> is cset or csetm.
• The <cond> is any one of the codes from Table 3.2 on page 59.
• The <nzcv> is any number 0-15 (0x0-0xf). It is four bits representing the N, Z, C, and V
flags.
• The <imm5> is an unsigned 5-bit immediate.

4.2.10.2 Operations

Name Effect Description
csel if < cond > then Set Rd to Rn or Rm.
Rd ← Rn
else
Rd ← Rm
end if
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