Propeller Manual

TJNZ – Assembly Language Reference
TJNZ
Instruction: Test value and jump to address if not zero.
TJNZ Value, 〈#〉 Address
• Value (d-field) is the register to test.
•
Address (s-field) is the register or a 9-bit literal whose value is the address to jump to
when Value contains a non-zero number.
Opcode Table:
–INSTR– ZCRI –CON– –DEST– –SRC– Z Result C Result Result Clocks
111010 000i 1111 ddddddddd sssssssss
D = 0 0 Not Written 4 or 8
Concise Truth Table:
In Out
Destination Source Z C Effects Destination
1
Z C
$0000_0000; 0 $----_----; - - -
wr wz wc
$0000_0000; 0 1 0
$0000_0001; 1 $----_----; - - -
wr wz wc
$0000_0001; 1 0 0
1
Destination is not written unless the WR effect is given.
Explanation
TJNZ tests the Value register and jumps to Address if it contains a non-zero number.
When the
WZ effect is specified, the Z flag is set (1) if the Value register contains zero.
TJNZ requires a different amount of clock cycles depending on whether or not it has to jump.
If it must jump it takes 4 clock cycles, if no jump occurs it takes 8 clock cycles. Since loops
utilizing
TJNZ need to be fast, it is optimized in this way for speed.
Page 364 · Propeller Manual v1.1