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Instruction Set Description
4.6.3.7
BITX
BITX.A
Test bits set in source address-word in destination address-word
BITX.[W]
Test bits set in source word in destination word
BITX.B
Test bits set in source byte in destination byte
BITX.A src,dst
Syntax
BITX src,dst
or
BITX.W src,dst
BITX.B src,dst
Operation
src .and. dst
→
dst
Description
The source operand and the destination operand are logically ANDed. The result affects
only the status bits. Both operands may be located in the full address space.
Status Bits
N:
Set if result is negative (MSB = 1), reset if positive (MSB = 0)
Z:
Set if result is zero, reset otherwise
C:
Set if the result is not zero, reset otherwise. C = (.not. Z)
V:
Reset
Mode Bits
OSCOFF, CPUOFF, and GIE are not affected.
Example
Test if bit 16 or 15 of R5 (20-bit data) is set. Jump to label TONI if so.
BITX.A
#018000h,R5
; Test R5.16:15 bits
JNZ
TONI
; At least one bit is set
...
; Both are reset
Example
A table word pointed to by R5 (20-bit address) is used to test bits in R7. Jump to label
TONI if at least one bit is set.
BITX.W
@R5,R7
; Test bits in R7: C = .not.Z
JC
TONI
; At least one is set
...
; Both are reset
Example
A table byte pointed to by R5 (20-bit address) is used to test bits in input Port1. Jump to
label TONI if no bit is set. The next table byte is addressed.
BITX.B
@R5+,&P1IN
; Test input P1 bits. R5 + 1
JNC
TONI
; No corresponding input bit is set
...
; At least one bit is set
192
CPUX
SLAU272C – May 2011 – Revised November 2013
Copyright © 2011–2013, Texas Instruments Incorporated