Sign extend two Bytes with Add, to extend two 8-bit values to two 16-bit values.
is an optional condition code.
is the destination register.
is the register holding the number to add.
is the register holding the value to extend.
is one of:
is rotated right 8 bits.
is rotated right 16 bits.
is rotated right 24 bits.
is omitted, no rotation is performed.
This instruction does the following:
Rotate the value from
right by 0, 8, 16 or 24 bits.
Extract bits[23:16] and bits[7:0] from the value obtained.
Sign extend to 16 bits.
Add them to bits[31:16] and bits[15:0] respectively of
to form bits[31:16] and bits[15:0] of the result.
You cannot use PC for any register.
You can use SP in ARM instructions but this is deprecated in ARMv6T2 and above. You cannot use SP in Thumb instructions.
This instruction does not change the flags.
This ARM instruction is available in ARMv6 and above.
This 32-bit Thumb instruction is available in ARMv6T2 and above. For the ARMv7-M architecture, it is only available in an ARMv7E-M implementation.
There is no 16-bit version of this instruction in Thumb.