Freescale Semiconductor StarCore SC140 - Manual (Page 490)

A-176 SC140 DSP Core Reference Manual
IFc
IFc
Conditionally Execute a Group or Subgroup (PREFIX)
IFc
Description
These instructions add conditional control over a group or subgroup of instructions in a VLES.
Notes: 1. The instructions in the subgroups can be conditional (e.g., TFRT, JF), which adds finer
control.
2. The “IFA group” is the same as not using IFc. That is, unconditional execution of the VLES.
3. The detailed use of IFc is defined by
Section 7.2, “VLES Grouping Semantics,” and
programming rule G.P.7 in Section 7.5.3, “Prefix Grouping Rules.”
Operation Assembler Syntax
If T == 0, then execute group/subgroup
else treat as NOP IFF group or subgroup of instructions
If T == 1, then execute group/subgroup
else treat as NOP IFT group or subgroup of instructions
execute group/subgroup unconditionally IFA group or subgroup of instructions
IFF
Execute the group or subgroup if T is equal to zero (condition is false). If T is equal to one (condition is
true), the group or subgroup is treated as a NOP. This instruction can be used in conjunction with IFT to
form an if/else clause.
IFT
Execute the group or subgroup if T is equal to one (condition is true). If T is equal to zero (condition is
false), the group or subgroup is treated as a NOP. This instruction can be used in conjunction with IFF to
form an if/else clause.
IFA
Always execute the group or subgroup. This instruction may be used in conjunction with IFT or IFF to split
a VLES group into conditional and unconditional subgroups, where IFA must be the last subgroup in the
VLES.
The following combinations of these instructions can be used:
IFT group ; execute group if T is set
IFF group ; execute group if T is clear
IFA group ; execute group unconditionally
IFT subgroup1 IFA subgroup2 ; execute subgroup1 if T is set,
; execute subgroup2 unconditionally
IFF subgroup1 IFA subgroup2 ; execute subgroup1 if T is clear,
; execute subgroup2 unconditionally
IFT subgroup1 IFF subgroup2 ; execute subgroup1 if T is set,
; execute subgroup2 if T is clear