Freescale Semiconductor StarCore SC140 - Manual (Page 379)

BF
SC140 DSP Core Reference Manual A-65
B
BF
Branch If False (AGU)
BF
Description
Status and Conditions that Affect Instruction
Status and Conditions Changed by Instruction
None.
Example
BF lbl
Operation Assembler Syntax
If T==0, then PC + displacement
→ PC
BF <label
BF >label
BF <label
BF >label
Branches to label if the true bit is cleared. If the T bit is cleared, the program continues executing at
location PC + displacement. If the T bit is set, the PC is updated to point to the next execution set, and the
program continues executing sequentially. The displacement, calculated by the assembler and linker, is a
two’s complement integer that represents the relative distance from the current PC to the destination label.
The assembler determines if the PC relative displacement is a short branch (
<label [–2
8
≤ displacement <
2 8 , W]) or a long branch (
>label [–2
20
≤ displacement < –2
8 , W and 2 8
≤ displacement < 2
20 , W]).
Register Address Bit Name Description
SR[1] T True bit
Instruction Result
cmpeq.w #$35,d1 Not equal, so T bit in SR cleared.
bf lbl move.w #$29,d1 Branch taken, move.w executed.
inc d1 Skipped over.
move.w #$47,d2 Skipped over.
- - - - Skipped over.
- - - - Skipped over.
- - - - Skipped over.
lbl move.w #$16,d4 Execution continues here at lbl.
Register/Memory Address Before After
SR $00E4 0000
d1 $0000 $0029