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INSTRUCTION SET S3C84E5/C84E9/P84E9
6-24
BTJRT — Bit Test, Jump Relative on True
BTJRT dst,src.b
Operation: If src(b) is a "1", then PC ← PC + dst
The specified bit within the source operand is tested. If it is a "1", the relative address is added to
the program counter and control passes to the statement whose address is now in the PC.
Otherwise, the instruction following the BTJRT instruction is executed.
Flags: No flags are affected.
Format:
(note)
Bytes Cycles Opcode
(Hex)
Addr Mode
dst src
opc src | b | 1 dst 3 10 37 RA rb
NOTE: In the second byte of the instruction format, the source address is four bits, the bit address "b" is
three bits, and the LSB address value is one bit in length.
Example: Given: R1 = 07H:
BTJRT SKIP,R1.1
If the working register R1 contains the value 07H (00000111B), the statement "BTJRT SKIP,R1.1"
tests bit one in the source register (R1). Because it is a "1", the relative address is added to the PC
and the PC jumps to the memory location pointed to by the SKIP.
Remember that the memory location addressed by the BTJRT instruction must be within the allowed
range of + 127 to – 128.