A-65
INSTRUCTION SET REFERENCE
JB bit51,rel
JB bit,rel
Function:
Jump if bit set
Description:
If the specified bit is a one, jump to the address specified; otherwise proceed with the next
instruction. The branch destination is computed by adding the signed relative displacement
in the third instruction byte to the PC, after incrementing the PC to the first byte of the next
instruction. The bit tested is not modified.
Flags:
Example:
Input port 1 contains 11001010B and the accumulator contains 56 (01010110B). After the
instruction sequence
JB P1.2,LABEL1
JB ACC.2,LABEL2
program execution continues at label LABEL2.
Variations
JB bit51,rel
Binary Mode
Source Mode
Not Taken
Taken
Not Taken
Taken
Bytes:
3
3
3
3
States:
2
5
2
5
Hex Code in:
Binary Mode = [Encoding]
Source Mode = [Encoding]
Operation:
JB
(PC)
←
(PC) + 3
IF (bit51) = 1
THEN
(PC)
←
(PC) + rel
JB bit,rel
Binary Mode
Source Mode
Not Taken
Taken
Not Taken
Taken
Bytes:
5
5
4
4
States:
4
7
3
6
[Encoding]
Hex Code in:
Binary Mode = [A5][Encoding]
Source Mode = [Encoding]
CY
AC
OV
N
Z
—
—
—
—
—
[Encoding]
0 0 1 0
0 0 0 0
bit addr
rel. addr
1 0 1 0
1 0 0 1
0 0 1 0
0
y y
direct addr
rel. addr
Содержание 8XC251SA
Страница 2: ......
Страница 3: ...May 1996 8XC251SA 8XC251SB 8XC251SP 8XC251SQ Embedded Microcontroller User s Manual...
Страница 18: ......
Страница 19: ...1 Guide to This Manual...
Страница 20: ......
Страница 30: ......
Страница 31: ...2 Architectural Overview...
Страница 32: ......
Страница 41: ...3 Address Spaces...
Страница 42: ......
Страница 63: ...4 Device Configuration...
Страница 64: ......
Страница 81: ...5 Programming...
Страница 82: ......
Страница 102: ......
Страница 103: ...6 Interrupt System...
Страница 104: ......
Страница 120: ......
Страница 121: ...7 Input Output Ports...
Страница 122: ......
Страница 132: ......
Страница 133: ...8 Timer Counters and Watchdog Timer...
Страница 134: ......
Страница 153: ...9 Programmable Counter Array...
Страница 154: ......
Страница 170: ......
Страница 171: ...10 Serial I O Port...
Страница 172: ......
Страница 187: ...11 Minimum Hardware Setup...
Страница 188: ......
Страница 197: ...12 Special Operating Modes...
Страница 198: ......
Страница 206: ......
Страница 207: ...13 External Memory Interface...
Страница 208: ......
Страница 239: ...14 Programming and Verifying Nonvolatile Memory...
Страница 240: ......
Страница 250: ......
Страница 251: ...A Instruction Set Reference...
Страница 252: ......
Страница 390: ......
Страница 391: ...B Signal Descriptions...
Страница 392: ......
Страница 400: ......
Страница 401: ...C Registers...
Страница 402: ......
Страница 436: ......
Страница 437: ...Glossary...
Страница 438: ......
Страница 446: ......
Страница 447: ...Index...
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Страница 458: ......