BT
SC140 DSP Core Reference Manual
A-109
BT
Branch If True (AGU)
BT
Description
Status and Conditions that Affect Instruction
Status and Conditions Changed by Instruction
None.
Example
BT lbl
Operation
Assembler Syntax
If T==1, then PC + displacement
→
PC
BT <label
BT >label
BT <label
BT >label
Branches to label if the true bit is set. If the T bit is set, the program continues executing at location
PC + displacement. If the T bit is cleared, 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
Equal, so T bit in SR set.
bt lbl move.w #$29,d1
Branch taken, move.w executed, d1=$29.
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, d4=$16.
Register/Memory Address
Before BT
After
SR
$00E4 0002
d1
$0035
$0029
Содержание SC140 DSP Core
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Страница 32: ...1 6 SC140 DSP Core Reference Manual Core Architecture Features ...
Страница 180: ...4 70 SC140 DSP Core Reference Manual Trace Unit Registers ...
Страница 250: ...6 70 SC140 DSP Core Reference Manual Programming Rules ...
Страница 314: ...7 64 SC140 DSP Core Reference Manual NOP Definition ...
Страница 385: ...BMCHG W SC140 DSP Core Reference Manual A 71 u16 iiiiiiiiiiiiiiii 16 bit unsigned immediate data ...
Страница 388: ...A 74 SC140 DSP Core Reference Manual BMCHG W s16 AAAAAAAAAAAAAAAA 16 bit signed SP address offset ...
Страница 391: ...BMCLR SC140 DSP Core Reference Manual A 77 u16 iiiiiiiiiiiiiiii 16 bit unsigned immediate data ...
Страница 454: ...A 140 SC140 DSP Core Reference Manual DECA u5 iiiii 5 bit unsigned immediate data 1 set by the assembler ...
Страница 463: ...DI SC140 DSP Core Reference Manual A 149 15 8 7 0 DI 1 1 4 1 0 0 1 1 1 1 1 0 1 1 1 1 1 0 1 ...
Страница 478: ...A 164 SC140 DSP Core Reference Manual EI ...
Страница 592: ...A 278 SC140 DSP Core Reference Manual MOVE L a32 aaaaaaaaaaaaaaaaAAAAAAAAAAAAAAAA 32 bit absolute long address ...
Страница 618: ...A 304 SC140 DSP Core Reference Manual MOVES 4F s15 sssssssssssssss Signed 15 bit offset ...
Страница 638: ...A 324 SC140 DSP Core Reference Manual MPYR ...
Страница 660: ...A 346 SC140 DSP Core Reference Manual OR W s16 AAAAAAAAAAAAAAAA Signed 16 bit SP address offset ...
Страница 746: ...A 432 SC140 DSP Core Reference Manual ZXTA x ...
Страница 758: ...I 10 Index ...
Страница 759: ...SC140 DSP Core Reference Manual i ...
Страница 760: ......