Building a COFFEE POT simulation on CCESS for Blackfin BF533

Transcription

1 Building a COFFEE POT simulation on CCESS for Blackfin BF533 Last lecture covered some detailed ideas Let step back and do something simpler to get an introduction of ideas needed for Lab0 and Assignment 1 CCES is based on Eclipse Continued

2 First steps in Assignment 1 We have Built a Project and then a main( ) as a driver of other functions meaning make calls to other functions no detailed code Software Engineering concept Abstraction as an approach to simplify coding and testing Need to discuss what it is important to understand the difference between Introduced Error and Discovered Defect and impact on time spent when developing assignments and labs (and quizzes and life) We will solve and prevent problems by CODE REVIEW to avoid L.S.D.s like typos (Compiler messages) Adding our own header files (fix Unresolved compiler messages) Adding a library (system errors) linker messages Adding STUBs for our own functions to resolve linker errors RUN A TEST ON MAIN Checks that system (hardware and software is functioning) Check that the program flow is correct by calling functions the functions are stubs, perhaps without all the full code detail

3 PSP Start with a Test does systemstill work main( ) to CoffeePot_main.cpp Before clicking Build project to activate the compiler Do a CODE REVIEW BEFORE compiling (PSP Personal Software Process) Fix all syntax errors that editor is telling you about The number of syntax found by compiler and not you indicates possible logical mistakes (now DEFECTS) left behind in your code not found by you or compiler and likely to cause time waste later Mistakes of the type LOGICAL DEFECTS will take MUCH time to correct as you DON T KNOW when you made them, where they are, and what knock on effect they are having!

4 My Personal Software Process (PSP) Never more than ideas to think about Never have code segment that occupies more than a screen (Turn screen long ways is a partial fix) If code occupies more than a screen then move code portions into a subroutine / function S.E. Abstraction Plan the project in parts S.E. Abstraction less to worry about at one time Do things in a standard order so you do the right things automatically (PSP)^2) Practice Safe Programming in PSP Make code readable to yourself later (when stressed out (always)) Make main( ) a series of calls to functions (flow, 7 + 2); Add YOUR function prototypes (interface) into header (no compiler defects) Add stubs (placeholder code) for all your functions (no linker defects) Compile, Link, Download, Run and (IYAG) move to next stage

5 Plan Ahead in small chunks Need to tell simulator how many coffeepots you want to simulate adding to the embedded system Check that simulator set up the number of coffeepots Find out where the plug and play control system placed the coffeepots you requested (hardware addresses to access) Control whether you will do simulation using functions written C / C++ code or using Assembly code (Need both) Watch for some hints about doing the more complex Assignment 2 where you control rather than display coffeepots Learn how to recognize some standard LSD issues LSD are Little Stupid Details causing catastrophic errors

6 How to waste BEACOUP de temps in assignments and laboratories Ignore all the warning message from the IDE tools that your code is wrong Just activate Build project icon and watch and wait for errors to appear Get into PSP habit of Code Review as you go along

7 PSP Avoiding having header issues Are these Compiler or Linker defect messages? What PSP steps did the person forget to do to cause these errors? or are they defects? And why care? // More prototypes added as we move through assignment 1) COFFEPTOT1 2) Too few args Why might IDE cntrl space hot key help?

8 CoffeePot_SimulatorFunctions2017.h Look inside Name So everybody gets a different assignment Is it hot key Cntrl space for help (after F12 refresh)

9 Fixing two types of Linker errors you could have avoided with PSP code review Add Do_Simulation_CPP( ) STUB code to fix / avoid the linker error about our code Add Coffeepot Library.dlb (See Lab0 Familiarization) to fix / avoid other linker errors about SYSTEM CALLS

10 Rebuild project Ready to RUN TEST OF MAIN MAGIC You will get an error about missing Symbol USE_CCES_GUI_Delay when you link in Coffeepot2015 library (dlb) Add the following MAGIC code to MyCoffeePotFunctions_CPP.cpp WAIL void USE_CCES_GUI_Delay(void) { /* DO NOTHING */ } BUILD PROJECT Then DEBUG AS and see what happens

11 Runtime Defect caused by mistake in defining COFFEEPOT1 in enum Computers count from 0; USERS count from 1 NOTE: I am running at home using a Blackfin533 simulator session (no hardware needed) Fix defect (error out of phase) and run again

12 Oh!! We all had a tragic accident Remember: Embedded Systems are safety critical, so Practice Safe Programming habits Real World Nobody remembered to plug in coffeepot embedded system crashed Embedded World Program tried to access nonexistent memory. This caused an EXCEPTION EMBEDDED SYSTEM FAILURE No EXCEPTION HANDLER was provided to printout message System will start aging as nothing plugged in so EVERYTHING TOTAL SYSTEM FAILED!

13 SIMULATING adding 4 MOCK coffeepot interfaces into embedded system Auto Plug and play You add in the interface (USB stick of coffeepot connection) The operating system assigns memory for the interface Manual Plug and play used here deliberately so you can get a chance to learn how to change how the LDF (Loader Descriptor File) manipulates the memory allocation inside any embedded system environment e.g. Code used fast on chip memory rather than slow external

14 Simulating plug and play operations Click on system.svc, then Startup Code / LDF, then LDF, then ADD (Stacks and Heaps) Add memory space for COFFEEPOT1 (Heap1), COFFEEPOT2 (Heap2). T.I.S. No save button so Control S to save LDF.

15 Go back to CCES, rebuild and run. Display you get with Init_CoffeePotSimulation(numCoffeePots_ToInstall, USE_TEXT_GUI); Click on project name (sets scope) Get coffeepot working first Click on CCES Coffeepot SCADA GUI menu and activate Long distance SCADA view of COFFEEPOT. (Click on LOCK option too)? Run your code again with Init_CoffeePotSimulation (numcoffeepots_toinstall, (WHICH DISPLAY) (USE TEXT GUI USE CCES GUI))

16 Plan a Do_Simulation_CPP( ) for a quick check that we understand and can do basic COFFEEPOT control PSP Make compiler happy PSP Make linker happy Put new prototypes at top of the first file that uses them Refactor to MyCoffeePot h So all files can call this function without introducing :defects

17 The control register has many fields (Parts that control switches of different things) NOTE: The design defect (no LED control) is accidentally fixed by designer BUT introduces a different design defect. Note: COFFEEPOD change in Customer Scope Details shown in documentation as follows Similar format in Blackfin manual for the registers used to control Blackfin on chip peripherals COFFEEPOT PERIPHERAL CONTROL REGISTER (CPCR) OFFSET 0x00 RESET 0x00 W1S, W0C LED CONTROL FIELD (Bits 15 to 12) 0x1 LED 1 0x2 LED 2 0x4 LED 3 0x8 LED 4 Can combine values in a field (Lab 0, Assign 1) 0x5 causes LED1 and LED3 to be on COFFEEPOD CONTROL FIELD (Bit 11) 0x1 Insert coffee pod GENERAL CONTROL (Bits 4 to 0) 0x1 b00001 Cause device to initialize (2 seconds) and stay powered up 0x2 b00010 Turns LED Power on (So LEDs work) 0x4 b00100 Turns Water control power on (So water will flow) 0x8 b01000 Turns Heater power on (So heating will occur) 0x10 b10000 Device is ready after initialization RO (read only) Can combine values in a field 0x6 (b00110) turns on BOTH LED and water power but deactivates the device (bit 0 = 0; so nothing works) NOTE: Design refactoring occurring LED and Coffeepod? control registers fields of CPCR READY BIT accounts for coffeepot is hardware and not software so not immediately ready You CAN T set the READY bit (its READ ONLY), the device itself sets that bit when running properly 17

18 Demonstrate we know what we are doing turn LED1 on LED CONTROL FIELD (Bits 15 to 12) 0x1 LED 1 0x2 LED 2 0x4 LED 3 0x8 LED 4 Lesson 1 on manipulating control fields If you WRITE a 1 (needs 1 << 12) into this field to turn on LED 1 you are actually writing b0001 The 1 on b0001 turns on LED 1 but the 0 s in b0001 turns OFF LEDs 2 to 4 So you must READ the field, OR a 1 into bit 12 (which leaves bits 13, 14, 15 unchanged) and then write back the changed and unchanged bits THIS LESSON FROM LAB0 DOES NOT WORK WHY

19 LEDS don t work unless we turn the LED power on COFFEEPOT PERIPHERAL CONTROL REGISTER (CPCR) OFFSET 0x00 RESET 0x00 W1S, W0C GENERAL CONTROL (Bits 4 to 0) 0x2 b00010 Turns LED Power on (So LEDs work) Write a 1 to LED Power on bit (needs 1 << 1) Does not work Reason 1 Writing 1 << 1 to the control register means we write b So we turn on bit 1 LED Power ON, but also turn off bit 12 a switch to turn LED 1 on / off And also we turn off the RESET bit which totally deactivates the processor

20 Pseudo code Activate bit 0 to turn on the processor baseaddress >control = 1 (b Wait till READY bit 4 turns on (b ) BIGGY ERROR WAIT TILL READY Now set LED power on (bit 1) with out turning off bits 0 and 4 unsigned short int temp1 = baseaddress >control; unsigned short int temp2 = (1 << 1); temp1 = temp1 temp2; // Bit wise OR baseaddress >control = temp1; See same syntax in the EWARM JEADI ARM articles DONE IN 4 STEPS OF THE SIMPLEST POSSIBLE C++ as that is the way you to be able to translate the code from C++ into assembly code

21 DONE IN 4 STEPS as that is the way you would have to do it in assembly code unsigned short int temp1 = baseaddress >control; R0 = W[P0] (Z); // switch 16 to 32 bits unsigned short int temp2 = (1 << 1); R1 = (1 << 1); temp1 = temp1 temp2; // Bit wise OR R0 = R0 R1; baseaddress >control = temp1; W[P0] = R0; // Switch 32 bits to 16 ssync; // Force Blackfin architecture to write PSP Write simple C++ code as that makes it easy to translate into assembly code

22 Now turn on LED1 and then off COFFEEPOT PERIPHERAL CONTROL REGISTER (CPCR) OFFSET 0x00 RESET 0x00 W1S, W0C #define LED1_ON_BIT 12 R0 = W[P0] (Z); // unsigned short int temp1 = baseaddress >control; R1 = (1 << LED1_ON_BIT ); // unsigned short int temp2 = (1 << LED1_ON_BIT ); R0 = R0 R1; // temp1 = temp1 temp2; // Bit wise OR W[P0] = R0; // baseaddress >control = temp1; ssync; // Force Blackfin architecture to write // LED 1 ON R0 = W[P0] (Z); // unsigned short int temp1 = baseaddress >control; R1 = (1 << LED1_ON_BIT ); // unsigned short int temp2 = (1 << LED1_ON_BIT ); R1 = ~R1; // Flip 1 0 and 0 1 with twiddle operator R0 = R0 & R1; // temp1 = temp1 & temp2; // Bit wise AND W[P0] = R0; // baseaddress >control = temp1; ssync; // Force Blackfin architecture to write // LED 1 ON

23 Back to discussion on turning WaterControl_CPP( ) into ASM What I am going to do is Design the CPP code on paper Then translate the CPP into ASM on paper without changing the design. Put the paper code into an ASM file and code review for errors. See what syntax errors CrossCore finds that you did not REMEMBER THE WAY YOU CODE NOW IS THE WAY YOU WILL CODE TOMORROW UNLESS YOU PIP Process Improvement Plan PIP CHOOSE 2 THINGS I GET WRONG ALL THE TIME AND CHECK FOR THOSE EACH TIME. ADD 2 MORE THINGS NEXT LAB / EXAM DSFQ The number of syntax errors CrossCore finds (and you did not) provides an estimate of all the mistakes you made and left behind as DEFECTS since logical errors is something that CrossCore can t find. USEFUL SKILL Will do a lecture on estimating the defects left behind

24 ASM code Add standard stuff first // #include all necessary include filesasm.h need at least #include <blackfinasm.h>.section data1; // Always something like this // Where we will place ASM variables when we need them PSP place holder for now.section program; // Always something like this.global _WaterControlCode_ASM; // ASM way of saying that function is NOT PRIVATE _WaterControlCode_ASM: // extern C void WaterControlCode_ASM( // COFFEEPOT_DEVICE *coffeepot_baseaddress, // SAVE non volatile // ^ INPAR 1 always passed in R0 // registers used // unsigned short int waterlevelrequired) // ^ INPAR 2 always passed in R1 LINK 20; // Special magic needed when calling functions from Blackfin ASM functions // { // unsigned int waterlevel = CurrentWaterLevel_CPP(coffeePot_BaseAddress); // while { // (waterlevel <= waterlevelrequired) // { // coffeepot_baseaddress > waterinflowregister = 200; // My_SimulateOneSecondPassing(); // waterlevel = CurrentWaterLevel_CPP(coffeePot_BaseAddress); // } /* END WHILE */ _WaterControlCode_ASM.END: UNLINK; // } // LINK and UNLINK always paired // RECOVER non volatile // NOTE SAVE BEFORE LINK; LINK NEEDS A NUMBER 20 ALWAYS WORKS // registers used // RECOVER AFTER UNLINK; UNLINK KNOW HOW MUCH TO UNLINK RTS; 24

25 ASM code Add the obvious.section program; // Always something like this.global _WaterControlCode_ASM; // ASM way of saying that function is NOT PRIVATE _WaterControlCode_ASM: // extern C void WaterControlCode_ASM( // COFFEEPOT_DEVICE *coffeepot_baseaddress, // SAVE non volatile // ^ INPAR 1 always passed in R0 // registers used // unsigned short int waterlevelrequired) LINK 20; // ^ INPAR 2 always passed in R1 // Special magic needed when calling functions from Blackfin ASM functions // {.extern CurrentWaterLevel_CPP_NM; // I show I know name mangling occurs CALL CurrentWaterLevel_CPP_NM; // unsigned int waterlevel = CurrentWaterLevel_CPP(coffeePot_BaseAddres waterlevel_r1 = returnvalue_r0 ; // Functions always return values in R0 BIG PROBLEM // while { // (waterlevel <= waterlevelrequired) returnvalue_r0 has // { destroyed INPAR_R0 // coffeepot_baseaddress > waterinflowregister = 200;.extern Z23 My_SimulateOneSecondPassingv; CALL Z23 My_SimulateOneSecondPassingv // My_SimulateOneSecondPassing(); Guess at name mangling.extern CurrentWaterLevel_CPP_NM; // I show I know name mangling occurs CALL CurrentWaterLevel_CPP_NM; // waterlevel = CurrentWaterLevel_CPP(coffeePot_BaseAddress); waterlevel_r1 = returnvalue_r0 ; // CUT AND PAST CODE // } /* END WHILE */ _WaterControlCode_ASM.END: UNLINK; // } // LINK and UNLINK always paired // RECOVER non volatile // NOTE SAVE BEFORE LINK; LINK NEEDS A NUMBER 20 ALWAYS WORKS // registers used // RECOVER AFTER UNLINK; UNLINK KNOW HOW MUCH TO UNLINK RTS; 2017 new Knowledge The 23 in the name mangled name means 23 letters in the C++ name (TAO OWYKTO) 25

26 Work on the while loop control.section program; // Always something like this.global _WaterControlCode_ASM; // ASM way of saying that function is NOT PRIVATE _WaterControlCode_ASM: // extern C void WaterControlCode_ASM( // COFFEEPOT_DEVICE *coffeepot_baseaddress, // SAVE non volatile // ^ INPAR 1 always passed in R0 // registers used // unsigned short int waterlevelrequired) LINK 20; // ^ INPAR 2 always passed in R1 // Special magic needed when calling functions from Blackfin ASM functions // {.extern CurrentWaterLevel_CPP_NM; // I show I know name mangling occurs CALL CurrentWaterLevel_CPP_NM; // unsigned int waterlevel = CurrentWaterLevel_CPP(coffeePot_BaseAddress waterlevel_r1 = returnvalue_r0 ; // Functions always return values in R0 THINK I WHILE_WCC: // while { CC = waterlevel_r1 <= INPAR2_R1 // (waterlevel <= waterlevelrequired) DOWN HILL IF!CC JUMP END_WHILE_CC // EXIT WHILE IF CONDITION IS NOT TRUE { GO WE // coffeepot_baseaddress > waterinflowregister = 200;.extern Z23 My_SimulateOneSecondPassingv; CALL Z23 My_SimulateOneSecondPassingv // My_SimulateOneSecondPassing(); Guess at name mangling.extern CurrentWaterLevel_CPP_NM; // I show I know name mangling occurs CALL CurrentWaterLevel_CPP_NM; // waterlevel = CurrentWaterLevel_CPP(coffeePot_BaseAddress); waterlevel_r1 = returnvalue_r0 ; // CUT AND PAST CODE JUMP WHILE_WCC; END_WHILE_WCC: // } /* END WHILE */ _WaterControlCode_ASM.END: UNLINK; // } // LINK and UNLINK always paired // RECOVER non volatile // NOTE SAVE BEFORE LINK; LINK NEEDS A NUMBER 20 ALWAYS WORKS // registers used // RECOVER AFTER UNLINK; UNLINK KNOW HOW MUCH TO UNLINK RTS; 26

27 Loop body need base address in P0.section program; // Always something like this.global _WaterControlCode_ASM; // ASM way of saying that function is NOT PRIVATE _WaterControlCode_ASM: // extern C void WaterControlCode_ASM( // COFFEEPOT_DEVICE *coffeepot_baseaddress, // SAVE non volatile // ^ INPAR 1 always passed in R0 // registers used // unsigned short int waterlevelrequired) LINK 20; // ^ INPAR 2 always passed in R1 // Special magic needed when calling functions from Blackfin ASM functions // {.extern CurrentWaterLevel_CPP_NM; // I show I know name mangling occurs CALL CurrentWaterLevel_CPP_NM; // unsigned int waterlevel = CurrentWaterLevel_CPP(coffeePot_BaseAddress waterlevel_r1 = returnvalue_r0 ; // Functions always return values in R0 DOWN HILL WHILE_WCC: // while { FAST GO CC = waterlevel_r1 <= INPAR2_R1 // (waterlevel <= waterlevelrequired) IF!CC JUMP END_WHILE_CC // EXIT WHILE IF CONDITION IS NOT TRUE { MORE WE baseaddress_p0 = INPAR1_R0; // coffeepot_baseaddress > waterinflowregister = 200; temp_r2 = 200; // Number values can t be placed in memory only register values can B[P0 + waterflowoffset] = temp2;.extern Z23 My_SimulateOneSecondPassingv; CALL Z23 My_SimulateOneSecondPassingv // My_SimulateOneSecondPassing(); Guess at name mangling.extern CurrentWaterLevel_CPP_NM; // I show I know name mangling occurs CALL CurrentWaterLevel_CPP_NM; // waterlevel = CurrentWaterLevel_CPP(coffeePot_BaseAddress); waterlevel_r1 = returnvalue_r0 ; // CUT AND PAST CODE JUMP WHILE_WCC; END_WHILE_WCC: // } /* END WHILE */ _WaterControlCode_ASM.END: UNLINK; // } // LINK and UNLINK always paired // RECOVER non volatile // NOTE SAVE BEFORE LINK; LINK NEEDS A NUMBER 20 ALWAYS WORKS // registers used // RECOVER AFTER UNLINK; UNLINK KNOW HOW MUCH TO UNLINK RTS; 27

28 Code review, save / recover INPAR_R1 to R4 Why?.section program; // Always something like this.global _WaterControlCode_ASM; // ASM way of saying that function is NOT PRIVATE _WaterControlCode_ASM: // extern C void WaterControlCode_ASM( [ SP] = R4; // COFFEEPOT_DEVICE *coffeepot_baseaddress, INPAR1_COPY_R4 = INPAR1_R0; // ^ INPAR 1 always passed in R0 [ SP] = R5; // unsigned short int waterlevelrequired) INPAR2_COPY_R5 = INPAR2_R1 // ^ INPAR 2 always passed in R1 LINK 20; // Special magic needed when calling functions from Blackfin ASM functions // {.extern CurrentWaterLevel_CPP_NM; // I show I know name mangling occurs allthats necessary for Quiz 1 CALL CurrentWaterLevel_CPP_NM; // unsigned int waterlevel = CurrentWaterLevel_CPP(coffeePot_BaseAddress); waterlevel_r1 = returnvalue_r0 ; // Functions always return values in R0 WHILE_WCC: // while { CC = waterlevel_r1 <= INPAR2_COPY_R5; // (waterlevel <= waterlevelrequired) IF!CC JUMP END_WHILE_CC ; // EXIT WHILE IF CONDITION IS NOT TRUE { baseaddress_p0 = INPAR1_COPY R4; // coffeepot_baseaddress > waterinflowregister = 200; temp_r2 = 200; // Number values can t be placed in memory only register values can B[P0 + waterflowoffset] = temp_r2;.extern Z23 My_SimulateOneSecondPassingv; CALL Z23 My_SimulateOneSecondPassingv // My_SimulateOneSecondPassing(); Guess at name mangling.extern CurrentWaterLevel_CPP_NM; // I show I know name mangling occurs CALL CurrentWaterLevel_CPP_NM; // waterlevel = CurrentWaterLevel_CPP(coffeePot_BaseAddress); waterlevel_r1 = returnvalue_r0 ; // CUT AND PAST CODE JUMP WHILE_WCC; END_WHILE_WCC: // } /* END WHILE */ _WaterControlCode_ASM.END: UNLINK; // } // LINK and UNLINK always paired R4 = [SP++]; // NOTE SAVE BEFORE LINK; LINK NEEDS A NUMBER 20 ALWAYS WORKS R5 = [SP++]; // RECOVER AFTER UNLINK; UNLINK KNOW HOW MUCH TO UNLINK RTS; DOWN HILL FAST GO MORE WE TREE INTO YES 28

29 Totally acceptable exam answer 90% This error is NOT fixed Program will crash in a very nasty way

30 These define must be added in real life if we want the code to assemble

31 This demonstrates my PSP for turning CPP into ASM Through my PSP I have learnt that I can generate 20 LOC / hr (on a good day) if I have to design, code and test the project If the design is already there then I can probably handle LOC /hr (on a good day) Unless I am careful (and not tired) I typically make 80 mistakes per 1 kloc (1 error every 9 lines) at the start of term I can get down to mistakes per 1 kloc by the end of term I don t spend enough time reviewing If spend 10 minutes coding spend 3 minutes reviewing

32 In the code above I did a code review, and I don t think I have made any syntax errors I KNOW that the assembler will not pick out the LOGICAL DEFECTS I introduced after the UNLINK This means that the program will probably crash after the RTS (return from subroutine to C++) My PSP says if the compiler picks up more syntax errors then there are probably more logical defects present in the code (about 3 to 1) I still have to link the ASM file to the project and test the code using the tests I used to check that the C++ code version works And there is a nasty hidden logical error waiting to byte me

33 Here is the result of the assemble Attempt 1 3 syntax errors I missed with the assembler then refusing to continue WHAT S YOUR SCORE? Attempt 2 2 new syntax errors Then success (with 2 hidden LOGICAL DEFECTS) 5 errors in 48 lines of code needs a PIP for PSP