Datasheet

161
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
Examples
UQASX R7, R4, R2 ; Adds top halfword of R4 with bottom halfword of R2,
; saturates to 16 bits, writes to top halfword of R7
; Subtracts top halfword of R2 from bottom halfword of
; R4, saturates to 16 bits, writes to bottom halfword of R7
UQSAX R0, R3, R5 ; Subtracts bottom halfword of R5 from top halfword of R3,
; saturates to 16 bits, writes to top halfword of R0
; Adds bottom halfword of R4 to top halfword of R5
; satur
ates to 16 bits, writes to bottom halfword of R0.
12.6.7.7 UQADD and UQSUB
Saturating Add and Saturating Subtract Unsigned.
Syntax
op{cond} {Rd}, Rn, Rm
op{cond} {Rd}, Rn, Rm
where:
op is one of:
UQADD8 Saturating four unsigned 8-bit integer additions.
UQADD16 Saturating two unsigned 16-bit integer additions.
UDSUB8 Saturating four unsigned 8-bit integer subtractions.
UQSUB16 Saturating two unsigned 16-bit integer subtractions.
cond is an optional condition code, see “Conditional Execution” .
Rd is the destination register.
Rn, Rm are registers holding the first and second operands.
Operation
These instructions add or subtract two or four values and then writes an unsigned saturated value in the destination
register.
The UQADD16 instruction:
 Adds the respective top and bottom halfwords of the first and second operands.
 Saturates the result of the additions for each halfword in the destination register to the unsigned range 0 ≤ x ≤ 2
16
-
1, where x is 16.
The UQADD8 instruction:
 Adds each respective byte of the first and second operands.
 Saturates the result of the addition for each byte in the destination register to the unsigned range 0 ≤ x ≤ 2
8
-1,
where x is 8.
The UQSUB16 instruction:
 Subtracts both halfwords of the second operand from the respective halfwords of the first operand.
 Saturates the result of the differences in the destination register to the unsigned range 0 ≤ x ≤ 2
16
-1, where x is 16.
The UQSUB8 instructions:
 Subtracts the respective bytes of the second operand from the respective bytes of the first operand.
 Saturates the results of the differences for each byte in the destination register to the unsigned range 0 ≤ x ≤ 2
8
-1,
where x is 8.
Restrictions
Do not use SP and do not use PC
.
Condition Flags