Uqadd And Uqsub - ARM Cortex-M4 Generic User Manual

3.7.7

UQADD and UQSUB

ARM DUI 0553A
ID121610
Saturating Add and Saturating Subtract Unsigned.
Syntax
op{cond} {Rd}, Rn, Rm
op{cond} {Rd}, Rn, Rm
where:
Is one of:
op
Saturating four unsigned 8-bit integer additions.
UQADD8
Saturating two unsigned 16-bit integer additions.
UQADD16
Saturating four unsigned 8-bit integer subtractions.
UDSUB8
Saturating two unsigned 16-bit integer subtractions.
UQSUB16
Is an optional condition code, see
cond
Specifies the destination register.
Rd
Are registers holding the first and second operands.
Rn, Rm
Operation
These instructions add or subtract two or four values and then writes an unsigned saturated value
in the destination register.
The instruction:
UQADD16
• 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
The instruction:
UQADD8
• 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
8
range 0 ≤ x ≤ 2 −1, where x is 8.
The instruction:
UQSUB16
• 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 instructions:
UQSUB8
• 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
Restrictions
Do not use SP and do not use PC
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Non-Confidential
Conditional execution on page
16 −1, where x is 16.
8 −1, where x is 8.
.
The Cortex-M4 Instruction Set
3-18.
3-105