For 68HC11 and using its instructions a Write a code fragmen

For 68HC11 and using its instructions. a) Write a code fragment which logically shifts left the 16-bit contents of $7900 (LeastSignificantBit) to 7901 (MostSignificantBit). b)Rewrite Part a using a right logical shift. The \"new\" bit should be zero and the out going bit can be ignored.

Solution

for 68c11 and using Microprocessors store their programs and data in memory. Memory is organized as a contiguous string of address, or locations. Each memory location contains eight bits of data (this is because the 68HC11 is an 8-bit micro; other processors can have 16 or 32 bits of data at each memory location).

The entire amount of memory that a processor can access is called its address space. The 68HC11 has an address space of 65,536 memory locations, corresponding exactly to 16 bits of address information. This means that a 16-bit numeral can be used to point at, or address, any of the memory bytes in the address space of the 68HC11. Thus four hexadecimal digits (4 bits per digit 4 digits) can exactly specify one memory location (in which the user will find one byte of information).

In general, any area of memory should be equivalent to any other. Because the 68HC11 is a special-purpose chip, and all of its memory is etched right on the microprocessor chip itself, its designers had to dedicate portions of its memory to particular functions. Figure 12.2 shows a  \"memory map\" of one of the members of the 68HC11 family of processors, the MC68HC811E2FN.

In this mode of operation, you perform all software development on the FreeBSD UNIX host and use a communications program such as kermit or minicom to access the target system. As you will have (most likely) compiled the cross assembler, you should also refer to the relevant cross assembler documentation. If the kermit communications program is used, run it with the -l switch to select a port e.g. kermit -l /dev/cuaa2, and make sure that your serial port (e.g. /dev/cuaa2) can be read from and written to by group dialer (as kermit changes its effective ID to dialer when run). The following default settings can be placed in a file such as ~/.kermrc-hc11