Atmel SAM4S Series, Preliminary Data Sheet

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157
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
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
; saturates to 16 bits, writes to bottom halfword of R0.
11.6.7.7 UQADD and UQSUB
Saturating Add and Saturating Subtract Unsigned.
Syntax
op{cond} {Rd}, Rn, Rm
op{cond} {Rd}, Rn, Rm
where:
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:
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.