INSTRUCTION SET S3C8245/P8245/C8249/P8249
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 1) 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 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
must be within the allowed range of + 127 to – 128.)