122-32000 Parallax Inc, 122-32000 Datasheet - Page 371

• Manufacturer Part Number: 122-32000
• Description: MANUAL PROPELLER
• Manufacturer: Parallax Inc

Specifications of 122-32000

• Accessory Type: Manual
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Effects
Every Propeller Assembly instruction has an optional “effects” field that causes it to modify a
flag or register when it executes. The basic syntax for Propeller Assembly instructions is:
〈
The optional Effects field can contain one of four conditions, shown below. For any effect
not specified, the default behavior remains as indicated by the corresponding bit (Z, C, or R)
in the
Follow an instruction with one to three space-delimited Effects to cause that instruction to
affect the indicated item. For example:
The first instruction performs a bitwise AND of the value in the
stores the result in
instruction performs a bitwise AND NOT of the value in the
modifies the Z flag according to whether or not the result is zero, and does not write the result
to
execution of the second instruction, the C flag is not altered. If these instructions did not
include the
Using Effects on instructions, along with Conditions on later instructions, enables code to be
much more powerful than what is possible with typical assembly languages. See Conditions
on page 368 for more information.
Label
temp2
〉 〈
ZCRI
. During the execution of the first instruction, the Z flag is not altered. During the
Condition
field of the instruction’s opcode.
WC
and
〉
WZ
Instruction
temp1
and
andn
effects, those flags would not be altered at all.
and modifies with C flag with the parity of the result. The second
Effect
WC
WZ
WR
NR
〈
Effects
temp1, #$20
temp2, #$38
〉
Table 5-3: Effects
Destination Register not modified
Destination Register modified
C Flag modified
Z Flag modified
Results In
wc
wz, nr
Propeller Manual v1.0 · Page 371
temp2
temp1
register with $38,
register with $20,