or the microsequencer. In the latter case, the data consists of an address to be used
for a branch instruction.The bus can also be used for the ALU or microsequencer to
provide data to other components.The System Y bus connects the ALU and floatingpoint
processor to local memory and to external modules via the PC interface.
The board fits into an IBM PC-compatible host computer.The host computer
provides a suitable platform for microcode assembly and debug.
Microinstruction Format
The microinstruction format for the 8800 consists of 128 bits broken down into
30 functional fields, as indicated in Table 16.7. Each field consists of one or more
bits, and the fields are grouped into five major categories:
• Control of board
• 8847 floating-point and integer processor chip