公开(公告)号：US4334268A

公开(公告)日：1982-06-08

申请号：US35138

申请日：1979-05-01

申请人： Joel F. Boney ,  Edward J. Rupp, II ,  James S. Thomas

发明人： Joel F. Boney ,  Edward J. Rupp, II ,  James S. Thomas

IPC分类号： G06F9/32

CPC分类号： G06F9/324 ,  G06F9/30058

摘要： A single-chip microcomputer comprises a central processor unit (100), a random access memory (110), a read only memory (120), internal timing circuitry including a timer counter (131), and three I/O data ports (140, 150, and 160). Included within the instruction set of the microcomputer are a branch on bit set instruction and a branch on bit clear instruction. The branch on bit set instruction is a three-byte instruction in which the first byte represents the op code including a designation of a particular bit to be examined, the second byte represents the address of a memory location in which the designated bit is to be examined, and the third byte represents an offset which when combined with the contents of the program counter designates a memory location to which a branch is to be taken if the designated bit is in fact set. For the branch on bit clear instruction, a branch is performed when the particular bit examined is determined not to be set. The branch on bit set and branch on bit clear instructions facilitate serial I/O operations by the microcomputer.

摘要翻译： 单片微计算机包括中央处理器单元（100），随机存取存储器（110），只读存储器（120），包括定时器计数器（131）的内部定时电路和三个I / O数据端口 ，150和160）。 包含在微机指令集中的是位置指令的分支和位清零指令的分支。 位设置指令上的分支是三字节指令，其中第一字节表示包括要检查的特定位的指定的操作码，第二字节表示指定位将被存储的存储器位置的地址 并且第三字节表示当与程序计数器的内容组合时指定如果实际设置了指定位时将要采用分支的存储器位置的偏移。 对于分支清零指令，当确定不被设置的特定位时，执行分支。 位上的分支和位清零指令分支便于微机的串行I / O操作。