Propeller Manual

WAITPNE – Assembly Language Reference
Page 370 · Propeller Manual v1.1
WAITPNE
Instruction: Pause a cog’s execution until I/O pin(s) do not match designated state(s).
WAITPNE State, 〈#〉 Mask
• State (d-field) is the register with the target state(s) to compare against INx ANDed
with Mask.
•
Mask (s-field) is the register or a 9-bit literal whose value is bitwise ANDed with INx
before the comparison with State.
Opcode Table:
–INSTR– ZCRI –CON– –DEST– –SRC– Z Result C Result Result Clocks
111101 000i 1111 ddddddddd sssssssss
--- --- Not Written 5+
Concise Truth Table:
In Out
Destination Source Z C Effects Destination
1
Z C
$0000_0000; 0 $0000_0000; 0 - -
wr wz wc
$0000_0000; 0 1 1
$0000_0000; 0 $0000_0001; 1 - -
wr wz wc
$0000_0002; 2 0 0
$0000_0001; 1 $0000_0001; 1 - -
wr wz wc
$0000_0003; 3 0 0
$0000_0000; 0 $0000_0002; 2 - -
wr wz wc
$0000_0003; 3 0 0
$0000_0002; 2 $0000_0002; 2 - -
wr wz wc
$0000_0002; 2 0 0
1
D estination is not written unless the WR effect is given.
Explanation
WAITPNE, “Wait for Pin(s) to Not Equal,” is one of four wait instructions (WAITCNT, T WAITPEQ,
WAITPNE, and WAITVID) used to pause execution of a cog until a condition is met. The WAITPNE
instruction pauses the cog until the result of INx ANDed with Mask does not match the value
in the State register.
INx is either INA or INB depending on the value of the C flag upon
execution;
INA if C = 0, INB if C = 1 (the P8X32A is an exception to this rule; it always tests
INA). The WAITPNE instruction behaves similar to Spin’s WAITPNE command; see WAITPNE on
page 224.