Extended Instructions
4-148
16-Bit MSP430X CPU
SUBX.A
Subtract source address-word from destination address-word
SUBX[.W]
Subtract source word from destination word
SUBX.B
Subtract source byte from destination byte
Syntax
SUBX.A
src,dst
SUBX
src,dst or SUBX.W
src,dst
SUBX.B
src,dst
Operation
(.not. src) + 1 + dst
→
dst
or dst − src
→
dst
Description
The source operand is subtracted from the destination operand. This is made
by adding the 1’s complement of the 1 to the destination. The source
operand is not affected. The result is written to the destination operand. Both
operands may be located in the full address space.
Status Bits
N:
Set if result is negative (src > dst), reset if positive (src <= dst)
Z:
Set if result is zero (src = dst), reset otherwise (src
≠
dst)
C:
Set if there is a carry from the MSB, reset otherwise
V:
Set if the subtraction of a negative source operand from a positive des-
tination operand delivers a negative result, or if the subtraction of a posi-
tive source operand from a negative destination operand delivers a
positive result, reset otherwise (no overflow).
Mode Bits
OSCOFF, CPUOFF, and GIE are not affected.
Example
A 20-bit constant 87654h is subtracted from EDE (LSBs) and EDE+2 (MSBs).
SUBX.A
#87654h,EDE
; Subtract 87654h from EDE+2|EDE
Example
A table word pointed to by R5 (20-bit address) is subtracted from R7. Jump to
label TONI if R7 contains zero after the instruction. R5 is auto-incremented by
2. R7.19:16 = 0
SUBX.W
@R5+,R7
; Subtract table number from R7. R5 + 2
JZ
TONI
; R7 = @R5 (before subtraction)
...
; R7 <> @R5 (before subtraction)
Example
Byte CNT is subtracted from the byte R12 points to in the full address space.
Address of CNT is within PC
±
512 K.
SUBX.B
CNT,0(R12)
; Subtract CNT from @R12
Note: Use SUBA for the following two cases for better density and execution.
SUBX.A
Rsrc,Rdst
or
SUBX.A
#imm20,Rdst
Содержание MSP430x4xx Family
Страница 1: ...MSP430x4xx Family 2007 Mixed Signal Products User s Guide SLAU056G ...
Страница 2: ......
Страница 6: ...vi ...
Страница 114: ...3 76 RISC 16 Bit CPU ...
Страница 304: ...5 20 FLL Clock Module ...
Страница 340: ...7 8 Supply Voltage Supervisor ...
Страница 348: ...8 8 16 Bit Hardware Multiplier ...
Страница 372: ...9 24 32 Bit Hardware Multiplier ...
Страница 400: ...10 28 DMA Controller ...
Страница 428: ...13 10 Basic Timer1 ...
Страница 466: ...15 24 Timer_A ...
Страница 522: ...17 30 USART Peripheral Interface UART Mode ...
Страница 544: ...18 22 USART Peripheral Interface SPI Mode ...
Страница 672: ...23 12 Comparator_A ...
Страница 692: ...24 20 LCD Controller ...
Страница 746: ...26 28 ADC12 ...