Zilog Z8F0130 - Manual (Page 124)

eZ8
™
CPU Core
User Manual
UM012820-0810 BTJZ Instruction
109
BTJZ
Definition
Bit Test and Jump if Zero.
Syntax
BTJZ bit, src, DA
Operation
if src[bit] = 0 {

PC
 PC + X
}
where the jump offset, X, is calculated by the eZ8 CPU assembler from
the Program Counter (PC) value and the Destination Address (DA).
Description
For this new eZ8 instruction, the selected bit in the source operand or reg-
ister pointed to by the source operand is compared with a logical 0. If the
selected bit is 0, the signed destination displacement (X) is added to the
Program Counter, that causes a jump. The displacement value can be from
–128 to +127. This instruction tests only a single bit position. Multiple
bits cannot be tested simultaneously.
Table 23. BTJZ Operand Description
Bit Position Tested Operand[3:0]
Decimal Binary Binary Hexadecimal
0 000 0000 0
1 001 0001 1
2 010 0010 2
3 011 0011 3
4 100 0100 4