Texas Instruments MSP430x4xx Family, User Manual

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Extended Instructions
4-150 16-Bit MSP430X CPU
SWPBX.A Swap bytes of lower word
SWPBX[.W] Swap bytes of word
Syntax SWPBX.A dst
SWPBX.W dst or SWPBX dst
Operation dst.15:8
à
dst.7:0
Description Register Mode: Rn.15:8 are swapped with Rn.7:0. When the .A extension is
used, Rn.19:16 are unchanged. When the .W extension is used, Rn.19:16 are
cleared.
Other Modes: When the .A extension is used, bits 31:20 of the destination
address are cleared, bits 19:16 are left unchanged, and bits 15:8 are swapped
with bits 7:0. When the .W extension is used, bits 15:8 are swapped with bits
7:0 of the addressed word.
Status Bits Not affected
Mode Bits OSCOFF, CPUOFF, and GIE are not affected.
Example Exchange the bytes of RAM address-word EDE.
MOVX.A #23456h,&EDE ; 23456h −> EDE
SWPBX.A EDE ; 25634h −> EDE
Example Exchange the bytes of R5.
MOVA #23456h,R5 ; 23456h −> R5
SWPBX.W R5 ; 05634h −> R5
Figure 4−55. Swap Bytes SWPBX.A Register Mode
15 8 7 0
15 8 7 0
Low Byte
Low Byte High Byte
High Byte
Before SWPBX.A
After SWPBX.A
X
X
19
19
16
16