<html> <head> <title>Execution commands of µCsim</title> </head> <body bgcolor="white"> <h2>Execution commands of µCsim</h2> <a name="run"><h3>r,run,go [start [stop]]</h3></a> This command starts the execution of the simulated program. <p>Parameters are optional. First parameter specifies start address of the execution. By default execution starts at address specified by actual value of the PC. This can be overridden by first parameter. <p>If second parameter is specified it places a dynamic breakpoint at specified address which stops the execution. If stop address is not given the simulator stops if it reaches a breakpoint, or the CPU accepts an interrupt and <b>stopit</b> option is TRUE, or fatal error occures or <a href="#stop">stop</a> command is used on an other console, or ENTER key is pressed on the console where the run command was issued. <p>If program execution is started the console is <i>frozen</i> it is not possible to give commands on this console to the simulator while execution is running. If it is needed to control the simulator during program execution then more consoles can be used. See using <a href="mulcons.html">multiple consoles</a> for more information. <p>Note that first instruction is executed without effect of breakpoints and simulation will be started afterwards. It means that if there is a breakpoint at start address then it will not be hit. See following example: <pre> $ <font color="#118811">./s51</font> ucsim 0.2.38-pre1, Copyright (C) 1997 Daniel Drotos, Talker Bt. ucsim comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. > <font color="#118811">b 0x10</font> Breakpoint 1 at 0x000010: MOV R7,A > <font color="#118811">b 0x20</font> Breakpoint 2 at 0x000020: MOV R7,A > <font color="#118811">run 0x10</font> Warning: maybe not instruction at 0x000010 Simulation started, PC=0x000010 Stop at 0x000020: (104) Breakpoint F 0x000020 > </pre> <hr> <a name="stop"><h3>stop</h3></a> This command stops the simulation, it freezes the CPU and all the peripherials. <pre> $ <font color="#118811">s51 remoansi.hex</font> ucsim 0.2.24, Copyright (C) 1997 Daniel Drotos, Talker Bt. ucsim comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. 58659 bytes read from remoansi.hex > <font color="#118811">g</font> Simulation started > <font color="#118811">dr</font> 000000 00 01 00 14 00 00 5a 47 ......ZG 000000 00 . ACC= 0x47 71 G B= 0x01 DPTR= 0x001c @DPTR= 0x47 71 G 000001 01 . PSW= 0x00 CY=0 AC=0 OV=0 P=0 006f02 90 00 1e MOV DPTR,#001e > <font color="#118811">stop</font> 006ac5 24 a5 ADD A,#a5 > </pre> Simulated program is executed in background and the simulator accepts commands. If it stopped by the stop command the instruction pointed by PC is dissassembled, see the <a href="#dis"><b>dis</b></a> command for description of disassembled form. <hr> <a name="step"><h3>s,step</h3></a> Step command. It executes one instruction without effect of breakpoints. <pre> $ <font color="#118811">s51 remoansi.hex</font> ucsim 0.2.12, Copyright (C) 1997 Daniel Drotos, Talker Bt. ucsim comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. 58659 bytes read from remoansi.hex > <font color="#118811">s</font> 000000 00 00 00 00 00 00 00 00 ........ 000000 00 . ACC= 0x00 0 . B= 0x00 DPTR= 0x0000 @DPTR= 0x00 0 . 000000 00 . PSW= 0x00 CY=0 AC=0 OV=0 P=0 000160 c2 90 CLR P1.0 > </pre> After execution of actual instruction pointed by PC the <b>step</b> command dumps out the register set. <hr> <a name="n"><h3>n,next</h3></a> Execute until next instruction is reached. This command is similar to <a href="#s"><b>step</b></a> command described above but if actual instruction to execute is a subroutine call the <b>next</b> command places a dynamic breakpoint after the call instruction and starts to execute the subroutine. If the subroutine is infinite the breakpoint set by <b>next</b> will never reached. It can be a dangerous situation because the executeion started by the <b>next</b> command can not be stopped interactively. But it can be stopped by other breakpoints. <pre> $ <font color="#118811">s51 remoansi.hex</font> ucsim 0.2.12, Copyright (C) 1997 Daniel Drotos, Talker Bt. ucsim comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. 58659 bytes read from remoansi.hex > <font color="#118811">run 0 0x172</font> 000172 79 04 MOV R1,#04 > <font color="#118811">dis 0x172 0 5</font> 000170 7f 00 MOV R7,#00 000172 79 04 MOV R1,#04 000174 12 0d b8 LCALL 0db8 000177 0f INC R7 000178 d9 fa DJNZ R1,0174 00017a 75 0b 00 MOV 0b,#00 > <font color="#118811">n</font> 000000 00 04 00 00 00 00 00 00 ........ 000000 00 . ACC= 0x00 0 . B= 0x00 DPTR= 0x0000 @DPTR= 0x00 0 . 000004 00 . PSW= 0x00 CY=0 AC=0 OV=0 P=0 000174 12 0d b8 LCALL 0db8 > <font color="#118811">n</font> 000000 00 04 00 00 00 00 00 00 ........ 000000 00 . ACC= 0x00 0 . B= 0x00 DPTR= 0x0167 @DPTR= 0x00 0 . 000004 00 . PSW= 0x00 CY=0 AC=0 OV=0 P=0 000177 0f INC R7 > </pre> <hr> <a name="pc"><h3>pc [address]</h3></a> Using this command without any parameter it simply dumps out instruction pointed by the PC. Specify address if you want to set the PC. <pre> $ s51 S51 0.1.5, Copyright (C) 1997 Daniel Drotos, Talker Bt. S51 comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. > <font color="#118811">pc</font> * 000000 ff MOV R7,A > <font color="#118811">pc 123</font> * 00007b ff MOV R7,A > <font color="#118811">sopt debug t </font> > <font color="#118811">pc 32</font> Warning: maybe not instruction at 000020 * 000020 ff MOV R7,A > </pre> <hr> <!--OK--> </body> </html>