Propeller Manual

3: Assembly Language Reference – TESTN
TESTN
Instruction: Bitwise AND a value with the NOT of another to affect flags only.
TESTN Value1, 〈#〉 Value2
Result: Optionally, zero-result and parity of result is written to the Z and C flags.
•
Value1 (d-field) is the register containing the value to bitwise AND with !Value2.
•
Value2 (s-field) is a register or a 9-bit literal whose value is inverted (bitwise NOT)
and bitwise ANDed with Value1.
Opcode Table:
–INSTR– ZCRI –CON– –DEST– –SRC– Z Result C Result Result Clocks
011001 000i 1111 ddddddddd sssssssss
D = 0 Parity of Result Not Written 4
Concise Truth Table:
In Out
Destination Source Z C Effects Destination
1
Z C
$F731_125A; -147,778,982 $FFFF_FFFA; -6 - -
wr wz wc
$0000_0000; 0 1 0
$F731_125A; -147,778,982 $FFFF_FFF8; -8 - -
wr wz wc
$0000_0002; 2 0 1
$F731_125A; -147,778,982 $FFFF_FFF0; -16 - -
wr wz wc
$0000_000A; 10 0 0
1
Destination is not written unless the WR effect is given. NOTE: the TESTN instruction with a WR effect is an ANDN instruction.
Explanation
TESTN is similar to ANDN except it doesn’t write a result to Value1; it performs a bitwise AND
NOT of Value2 into Value1 and optionally stores the zero-result and parity of the result in the
Z and C flags.
If the WZ effect is specified, the Z flag is set (1) if Value1 AND NOT Value2 equals zero. If
the
WC effect is specified, the C flag is set (1) if the result contains an odd number of high (1)
bits.
Propeller Manual v1.1 · Page 363