S3C3410X Datasheet, PDF (130/314 Pages) Samsung semiconductor – 16-Bit CMOS Microcontrollers

ARM INSTRUCTION SET
FORMAT 18: UNCONDITIONAL BRANCH
S3C3410X RISC MICROPROCESSOR
15 14 13 12 11 10
0
11100
Offset11
[10:0] Immediate Value
Figure 3-47. Format 18
OPERATION
This instruction performs a PC-relative Branch. The THUMB assembler syntax is shown below. The branch offset
must take account of the prefetch operation, which causes the PC to be 1 word (4 bytes) ahead of the current
instruction.
Table 3-25. Summary of Branch Instruction
THUMB assembler
B label
ARM equivalent
BAL label (halfword offset)
Action
Branch PC relative +/– Offset11 << 1, where label
is PC +/– 2048 bytes.
NOTE: The address specified by label is a full 12-bit two's complement address,
but must always be halfword aligned (ie bit 0 set to 0), since the assembler places label >> 1 in the Offset11 field.
EXAMPLES
here
B here
jimmy
B jimmy
•
•
•
•
; Branch onto itself. Assembles to 0xE7FE.
; (Note effect of PC offset).
; Branch to 'jimmy'.
; Note that the THUMB opcode will contain the number of
; halfwords to offset.
; Must be halfword aligned.
3-92