Propeller Manual

3: Assembly Language Reference – MAX
MAX
Instruction: Limit maximum of unsigned value to another unsigned value.
MAX Value1, 〈#〉 Value2
Result: Lesser of unsigned Value1 and unsigned Value2 is stored in Value1.
•
Value1 (d-field) is the register containing the value to compare against Value2 and is
the destination in which to write the lesser of the two.
•
Value2 (s-field) is a register or a 9-bit literal whose value is compared against Value1.
Opcode Table:
–INSTR– ZCRI –CON– –DEST– –SRC– Z Result C Result Result Clocks
010011 001i 1111 ddddddddd sssssssss
S = 0 Unsigned (D < S) Written 4
Concise Truth Table:
In Out
Destination
1
Source
1
Z C Effects Destination Z C
$0000_0001; 1 $0000_0000; 0 - -
wz wc
$0000_0000; 0 1 0
$0000_0001; 1 $0000_0001; 1 - -
wz wc
$0000_0001; 1 0 0
$0000_0001; 1 $0000_0002; 2 - -
wz wc
$0000_0001; 1 0 1
$0000_0000; 0 $0000_0001; 1 - -
wz wc
$0000_0000; 0 0 1
$0000_0001; 1 $0000_0001; 1 - -
wz wc
$0000_0001; 1 0 0
$0000_0002; 2 $0000_0001; 1 - -
wz wc
$0000_0001; 1 0 0
1
Both Source and Destination are treated as unsigned values.
Explanation
MAX compares the unsigned values of Value1 and Value2 and stores the lesser of the two into
the Value1 register, effectively limiting Value1 to a maximum of Value2.
If the
WZ effect is specified, the Z flag is set (1) if Value2 is zero (0). If the WC effect is
specified, the C flag is set (1) if the unsigned Value1 is less than the unsigned Value2. The
lesser of the two values is written to Value1 unless the
NR effect is specified.
Propeller Manual v1.1 · Page 307