Propeller Manual

3: Assembly Language Reference – ADD
ADD
Instruction: Add two unsigned values.
ADD Value1, 〈#〉 Value2
Result: Sum of unsigned Value1 and unsigned Value2 is stored in Value1.
•
Value1 (d-field) is the register containing the value to add to Value2 and is the
destination in which to write the result.
•
Value2 (s-field) is a register or a 9-bit literal whose value is added into Value1.
Opcode Table:
–INSTR– ZCRI –CON– –DEST– –SRC– Z Result C Result Result Clocks
100000 001i 1111 ddddddddd sssssssss
D + S = 0 Unsigned Carry Written 4
Concise Truth Table:
In Out
Destination
1
Source
1
Z C Effects Destination Z C
$FFFF_FFFE; 4,294,967,294 $0000_0001; 1 - -
wz wc
$FFFF_FFFF; 4,294,967,295 0 0
$FFFF_FFFE; 4,294,967,294 $0000_0002; 2 - -
wz wc
$0000_0000; 0 1 1
$FFFF_FFFE; 4,294,967,294 $0000_0003; 3 - -
wz wc
$0000_0001; 1 0 1
1
Both Source and Destination are treated as unsigned values.
Explanation
ADD sums the two unsigned values of Value1 and Value2 together and stores the result into the
Value1 register.
If the
WZ effect is specified, the Z flag is set (1) if Value1 + Value2 equals zero. If the WC
effect is specified, the C flag is set (1) if the summation resulted in an unsigned carry (32-bit
overflow). The result is written to Value1 unless the
NR effect is specified.
To add unsigned, multi-long values, use
ADD followed by ADDX. See ADDX on page 264 for
more information.
Propeller Manual v1.1 · Page 259