UM012811-0904
eZ8 CPU Instruction Set Description
eZ8 CPU
User Manual
81
BTJZ
Bit Test and Jump if Zero
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
The selected bit in the source operand or register pointed to by the source operand is com-
pared 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.
Figure 22. 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
5
101
0101
5
6
110
0110
6
7
111
0111
7
