Propeller Manual

SUMNZ – Assembly Language Reference
SUMNZ
Instruction: Sum a signed value with another whose sign is inverted depending on !Z.
SUMNZ SValue1, 〈#〉 SValue2
Result: Sum of signed SValue1 and ±SValue2 is stored in SValue1.
•
SValue1 (d-field) is the register containing the value to sum with either SValue2 or
-SValue2, and is the destination in which to write the result.
•
SValue2 (s-field) is a register or a 9-bit literal whose value is sign-affected by !Z and
summed into SValue1.
Opcode Table:
–
INSTR– ZCRI
–
CON
–
–
DEST–
–
SRC
–
Z Result C Result Result Clocks
100111 001i 1111 ddddddddd sssssssss
D ± S = 0 Signed Overflow Written 4
Concise Truth Table:
In Out
Destination Source Z C Effects Destination Z C
$0000_0001; 1 $0000_0001; 1 0 -
wz wc
$0000_0000; 0 1 0
$0000_0001; 1 $0000_0001; 1 1 -
wz wc
$0000_0002; 2 0 0
$0000_0001; 1 $FFFF_FFFF; -1 1 -
wz wc
$0000_0000; 0 1 0
$FFFF_FFFF; -1 $FFFF_FFFF; -1 0 -
wz wc
$0000_0000; 0 1 0
$FFFF_FFFF; -1 $FFFF_FFFF; -1 1 -
wz wc
$FFFF_FFFE; -2 0 0
$FFFF_FFFF; -1 $0000_0001; 1 1 -
wz wc
$0000_0000; 0 1 0
$8000_0000; -2,147,483,648 $0000_0001; 1 0 -
wz wc
$7FFF_FFFF; 2,147,483,647 0 1
$8000_0000; -2,147,483,648 $0000_0001; 1 1 -
wz wc
$8000_0001; -2,147,483,647 0 0
$8000_0000; -2,147,483,648 $FFFF_FFFF; -1 1 -
wz wc
$7FFF_FFFF; 2,147,483,647 0 1
$7FFF_FFFF; 2,147,483,647 $FFFF_FFFF; -1 0 -
wz wc
$8000_0000; -2,147,483,648 0 1
$7FFF_FFFF; 2,147,483,647 $FFFF_FFFF; -1 1 -
wz wc
$7FFF_FFFE; 2,147,483,646 0 0
$7FFF_FFFF; 2,147,483,647 $0000_0001; 1 1 -
wz wc
$8000_0000; -2,147,483,648 0 1
Explanation
SUMNZ (Sum with !Z-affected sign) adds the signed value of SValue1 to SValue2 (if Z = 1) or
to –SValue2 (if Z = 0) and stores the result into the SValue1 register.
If the
WZ effect is specified, the Z flag is set (1) if SValue1 ± SValue2 equals zero. If the WC
effect is specified, the C flag is set (1) if the summation resulted in a signed overflow. The
result is written to SValue1 unless the
NR effect is specified.
Page 358 · Propeller Manual v1.1