Propeller Manual

MAXS – Assembly Language Reference
MAXS
Instruction: Limit maximum of signed value to another signed value.
MAXS SValue1, 〈#〉 SValue2
Result: Lesser of signed SValue1 and signed SValue2 is stored in SValue1.
•
SValue1 (d-field) is the register containing the value to compare against SValue2 and
is the destination in which to write the lesser of the two.
•
SValue2 (s-field) is a register or a 9-bit literal whose value is compared against
SValue1.
Opcode Table:
–INSTR– ZCRI –CON– –DEST– –SRC– Z Result C Result Result Clocks
010001 001i 1111 ddddddddd sssssssss
S = 0 Signed (D < S) Written 4
Concise Truth Table:
In Out
Destination Source Z C Effects Destination Z C
$0000_0001; 1 $FFFF_FFFF; -1 - -
wz wc
$FFFF_FFFF; -1 0 0
$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
$FFFF_FFFF; -1 $0000_0001; 1 - -
wz wc
$FFFF_FFFF; -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
Explanation
MAXS compares the signed values of SValue1 and SValue2 and stores the lesser of the two into
the SValue1 register, effectively limiting SValue1 to a maximum of SValue2.
If the
WZ effect is specified, the Z flag is set (1) if SValue2 is zero (0). If the WC effect is
specified, the C flag is set (1) if the signed SValue1 is less than the signed SValue2. The
lesser of the two values is written to SValue1 unless the
NR effect is specified.
Page 308 · Propeller Manual v1.1