32-Bit Hardware Multiplier Operation
9-8
32-Bit Hardware Multiplier
MACS Underflow and Overflow
The multiplier does not automatically detect underflow or overflow in MACS
mode. For example working with 16-bit input data and 32-bit results, i.e. using
just RESLO and RESHI, the available range for positive numbers is 0 to
07FFF FFFFh and for negative numbers is 0FFFF FFFFh to 08000 0000h. An
underflow occurs when the sum of two negative numbers yields a result that
is in the range for a positive number. An overflow occurs when the sum of two
positive numbers yields a result that is in the range for a negative number.
The SUMEXT register contains the sign of the result in both cases described
above, 0FFFFh for a 32-bit overflow and 0000h for a 32-bit underflow. The
MPYC bit in MPY32CTL0 can be used to detect the overflow condition. If the
carry is different than the sign reflected by the SUMEXT register an overflow
or underflow occurred. User software must handle these conditions
appropriately.
Summary of Contents for MSP430x4xx Family
Page 1: ...MSP430x4xx Family 2007 Mixed Signal Products User s Guide SLAU056G ...
Page 2: ......
Page 6: ...vi ...
Page 114: ...3 76 RISC 16 Bit CPU ...
Page 304: ...5 20 FLL Clock Module ...
Page 340: ...7 8 Supply Voltage Supervisor ...
Page 348: ...8 8 16 Bit Hardware Multiplier ...
Page 372: ...9 24 32 Bit Hardware Multiplier ...
Page 400: ...10 28 DMA Controller ...
Page 428: ...13 10 Basic Timer1 ...
Page 466: ...15 24 Timer_A ...
Page 522: ...17 30 USART Peripheral Interface UART Mode ...
Page 544: ...18 22 USART Peripheral Interface SPI Mode ...
Page 672: ...23 12 Comparator_A ...
Page 692: ...24 20 LCD Controller ...
Page 746: ...26 28 ADC12 ...