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156
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
Examples
QDADD
R7, R4, R2
; Doubles and saturates R4 to 32 bits, adds R2,
; saturates to 32 bits, writes to R7
QDSUB
R0, R3, R5
; Subtracts R3 doubled and saturated to 32 bits
; from R5, saturates to 32 bits, writes to R0.
11.6.7.6
UQASX and UQSAX
Saturating Add and Subtract with Exchange and Saturating Subtract and Add with Exchange,
unsigned.
Syntax
op{cond} {Rd}, Rm, Rn
where:
Operation
The
UQASX
instruction:
1.
Adds the bottom halfword of the source operand with the top halfword of the second
operand.
2.
Subtracts the bottom halfword of the second operand from the top highword of the first
operand.
3.
Saturates the results of the sum and writes a 16-bit unsigned integer in the range
0
≤
x
≤
2
16
– 1, where
x
equals 16, to the top halfword of the destination register.
4.
Saturates the result of the subtraction and writes a 16-bit unsigned integer in the range
0
≤
x
≤
2
16
– 1, where
x
equals 16, to the bottom halfword of the destination register.
The
UQSAX
instruction:
1.
Subtracts the bottom halfword of the second operand from the top highword of the first
operand.
2.
Adds the bottom halfword of the first operand with the top halfword of the second
operand.
3.
Saturates the result of the subtraction and writes a 16-bit unsigned integer in the range
0
≤
x
≤
2
16
– 1, where
x
equals 16, to the top halfword of the destination register.
4.
Saturates the results of the addition and writes a 16-bit unsigned integer in the range 0
≤
x
≤
2
16
– 1, where
x
equals 16, to the bottom halfword of the destination register.
Restrictions
Do not use SP and do not use PC
.
Condition Flags
These instructions do not affect the condition code flags.
type
is one of:
UQASX
Add and Subtract with Exchange and Saturate.
UQSAX
Subtract and Add with Exchange and Saturate.
cond
is an optional condition code, see
Rd
is the destination register.
Rn, Rm
are registers holding the first and second operands.
Содержание SAM4S Series
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