第二种办法是顺序执行指令。一个程序由若干个程序段组成,每个程序段的指令可以设计成顺序地存放在存储器之中,所以只要指令地址寄存器兼有计数功能,在执行指令的过程中进行计数,自动加一个增量,就可以形成下一条指令的地址,从而达到顺序执行指令的目的。这个办法适用于以随机存储器
作为主存储器的计算机。当程序的运行需要从一个程序段转向另一个程序段时,可以利用转移指令来实现。转移指令中包含了即将转去的程序段入口指令的地址。执行转移指令时将这个地址送人程序计数器(此时只作为指令地址寄存器,不计数)作为下一条指令的地址,从而达到转移程序段的目的。子程序
的调用、中断
和陷阱的处理等都用类似的方法。在随机存取存储器普及以后
GENERAL ELECTRIC GE CR2940UN200C KEY OPERATED SWITCH D585405
ALLEN BRADLEY 1734-FPD POINT I/O FIELD DISTRIBUTOR MODULE SER B D588697
ALLEN BRADLEY 1769-IQ16 COMPACT I/O 16 PT INPUT MODULE SER A D586797
RAMSEY 110-150V 220-260V 1/4A 1/2A POWER MODULE D537945
MARATHON 1604 DJRC 72459 CASE OF 18 TERMINAL BLOCKS 600V-AC 75A AMP D553251
DIAMOND POWER 319100-1035 DELAY ALARM PCB CIRCUIT BOARD REV P D566147
MITSUBISHI JN354878-Y03 HOLDING COIL D567851
ELOBAU 46312110L SAFETY ConTROL UNIT 250V-AC 24V 90W 3A D571795
ALLEN BRADLEY 961502 96150294 REV A01 96150201G POWER SUPPLY D580987
PWB 115641-001123 6 SLOT MOTHERBOARD D582535
OMEGA FSW-30 FLOW SWITCH 1/2IN NPT D583511
TURCK RSM RKM 56-5M/S3059 5 POLE 10A AMP ConNECTOR D588567
CUTLER-HAMMER 10250T15111 SELECTOR SWITCH 2 POSITION MAINT SER A3 D592152
HonEYWELL C6097A1053 GAS PRESSURE SWITCH 120-240V-AC D595814
THOMAS&BETTS 60265 BOX OF 2 3/8 IN LUG TERMINAL ConNECTOR D544835
RITTAL SK3107 ENCLOSURE PANEL HEATER 230V-AC 200W D550322
FEDERAL SIGNAL 200D1036 A PCB POWER DISTRIBUTION CIRCUIT BOARD D541050
ABB YS-130 101-UH THYRISTOR D556381
FERRAZ SHAWMUT 66023 600V PDB 3P POWER DISTRIBUTION BLOCK D550845
ALLEN BRADLEY 20-COMM-P PROFIBUS COMMUNICATION MODULE SER A 5V-DC D550954
ANGLAND ELTEKNIK SA51 VIBRATION AMPLIFIER 0-25MM/S 115/230V-AC 4-20MA D548226
GE FANUC IC655CCM590A SERIES FIVE COMM RS232 ADAPTER UNIT D527333
GENERAL ELECTRIC GE 115PC119 PRESSURE SWITCH D538931
ALLEN BRADLEY 1746-OV32 SLC 500 SER C OUTPUT MODULE D553764
ALLEN BRADLEY 800HC-NX5 2-POSITION RED PUSH/PULL BUTTON SER A 24V-DC D568496
AGASTAT 7012PF 1-10MIN TIMING RELAY 125V-DC D565478
OPCON 8712A 102165 TIME DELAY RELAY 12V-DC D565710
ALLEN BRADLEY 871TS-N8BP12-D4 INDUCTIVE PROXIMITY SENSOR SER A D571262
TELEMECANIQUE C4BJK01 R.B DENISON LOX-SWITCH LIMIT SWITCH D567975
ALPHA WIRE 1555 18AWG STRANDED WIRE 1000FT BROWN 1000V-AC D572290
HITACHI BEH0800-0519816 MEMORY PCB CIRCUIT BOARD D584394
MICRO SWITCH 5ML7 PRECISION LIMIT SWITCH D587781
STRUTHERS-DUNN B255ABXP MAGNECRAFT RELAY 110/125V-DC D591480
MSD B255ABXP RELAY 115-125V-DC D591481
CAREL PCOUMI2000 PCO HUMIDIFIER INTERFACE MODULE 24V-AC D584369
DETECTOR SYSTEMS 1016-6 DIGITAL LOOP DETECTOR D588790
MERCOID PPQ-R-X3A 30IN-HG VACUUM TO 30IN-HG PRESSURE SWITCH D587609
WESTINGHOUSE 1163801 MG-6 MULTI-ConTACT AUXILIARY RELAY 125V-DC D585147
BANNER K30LGXYPQ 78802 EZ-LIGHT 2-COLOR INDICATOR D585349
GENERAL ELECTRIC GE CR2940UD212A3 INDICATOR LIGHT D588571
PALL 1200237 PCB CIRCUIT BOARD D588130
KRAUS & NAIMER C18 2AA106-600 E ROTARY SWITCH 20A AMP 600V-AC D589601
EMACHINES ET1641-02W DESKTOP COMPUTER TOWER 320GB 220-240V-AC 15A AMP D590253
SCOTT SCT096-2560 SCOUT GAS DETECTOR D586079
YOKOGAWA DB40 103111FAZZ7 PANEL METER 0-1600 DC AMPERES D586302
ALLEN BRADLEY 836-C7E PRESSURE SWITCH 24-600V-AC SER A D585915
TELEMECANIQUE 014386 XS518B1PAM12 INDUCTIVE PROXIMITY SWITCH 200MA D587266
MERCOID DPA-33-3-64 DIFFERENTIAL PRESSURE SWITCH 0-30PSI 120/240V-AC D587642