S06: Assembler / Linker Required: PM: Ch 7, pgs Assembler Directives

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1 S06: Assembler / Linker Required: PM: Ch 7, pgs Assembler Directives Recommended: MSP430 Assembly Tutorial MSP430 Disassembly.docx FUG: 3.4

2 CS 224 Chapter Lab Homework S00: Introduction Unit 1: Digital Logic
S01: Data Types S02: Digital Logic L01: Data Types L02: FSM HW01 HW02 Unit 2: ISA S03: ISA S04: Microarchitecture S05: Stacks / Interrupts S06: Assembly L03: Blinky L04: Microarch L05b: Traffic Light L06a: Morse Code HW03 HW04 HW05 HW06 Unit 3: C S07: C Language S08: Pointers S09: Structs S10: Threads S11: I/O L07b: Morse II L08a: Life L09b: Snake L10a: Threads HW07 HW08 HW09 HW10 BYU CS 224 Assembler / Linker

3 Learning Objectives… Learning Outcomes
After completing this section, you should be able to Explain the difference between a low level and high level language. Justify the study/use of assembly code. Contrast assembler directives with assembler code. Describe the assembly/linker process. Contrast a library with a computer program. Describe program sections and explain how they are used by the linker to create an executable. Give examples of emulated and intrinsic instructions. Use systematic decomposition to create an assembly program. Topics High Level vs. Assembly Assembly Instructions Emulated Instructions Assembler Assembly Code Assembly Sections Assembly Process Assembly Directives Linker Libraries Linking multiple files How to Code in Assembly Systematic Decomposition Lab 6a: Morse Code BYU CS 224 Assembler / Linker

4 High Level vs. Assembly High Level Languages Assembly Languages
More programmer friendly – easy to learn, easy to use, easy to understand More ISA independent Cross-platform compatible (portable) Each high-level statement translates to several instructions in the ISA of the computer Assembly Languages Lower level, ISA dependent Fewer data types – no distinction between program and data No programming restrictions Each instruction specifies a single ISA instruction Makes low level programming more user friendly More efficient code BYU CS 224 Assembler / Linker

5 High Level vs. Assembly Why Assembly Code? Allows us to work at a higher level than machine language (often called glorified machine code). Being closer to ISA may allow us to write more efficient code. No programming restrictions (lots of rope). Allows us to use symbolic names for opcodes and memory locations. add, call, push,… SUM, PRODUCT Don’t need to know every address of every storage location. Helps to allocate memory locations. Provides additional error checking. Calculates addresses for us – really a big deal! BYU CS 224 Assembler / Linker

6 Assembly Instructions

7 Double Operand Double Operand Instructions Mnemonic Operation
Description Arithmetic instructions ADD(.B or .W) src,dst src+dstdst Add source to destination ADDC(.B or .W) src,dst src+dst+Cdst Add source and carry to destination DADD(.B or .W) src,dst src+dst+Cdst (dec) Decimal add source and carry to destination SUB(.B or .W) src,dst dst+.not.src+1dst Subtract source from destination SUBC(.B or .W) src,dst dst+.not.src+Cdst Subtract source and carry from destination Logical and register control instructions AND(.B or .W) src,dst src.and.dstdst AND source with destination BIC(.B or .W) src,dst .not.src.and.dstdst Clear bits in destination BIS(.B or .W) src,dst src.or.dstdst OR (set) bits in destination BIT(.B or .W) src,dst src.and.dst Test bits in destination XOR(.B or .W) src,dst src.xor.dstdst XOR source with destination Data instructions CMP(.B or .W) src,dst dst-src Compare source to destination MOV(.B or .W) src,dst srcdst Move source to destination BYU CS 224 Assembler / Linker

8 Single Operand Double Operand Instructions Mnemonic Operation
Description RRC(.B or .W) src C  MSB  MSB− LSB+1  LSB  C Rotate right thru carry SWPB(.W) src Bits 15 to 8 <−> bits 7 to 0 Swap bytes RRA(.B or .W) src MSB  MSB, MSB  MSB−1, ... LSB+1  LSB, LSB  C Rotate right arithmetic SXT(.W) src Bit 7 → Bit Bit 15 Sign extend byte PUSH(.B or .W) src SP-2SP, Push byte/word source on stack CALL(.W) dst dsttmp ,SP-2SP, tmpPC Subroutine call to destination RETI TOSSR, SP+2SP TOSPC, SP+2SP Return from interrupt BYU CS 224 Assembler / Linker

9 Relative Jump Instructions
Double Operand Instructions Relative Jump Instructions PC-relative jumps, adding twice the sign-extended offset to the PC, for a jump range of to Mnemonic Operation Description JNZ/JNE Jump if Z == 0 Jump if not equal (if !=) JZ/JEQ Jump if Z == 1 Jump if equal (if ==) JNC/JLO Jump if C == 0 Jump if carry (if unsigned <) JC/JHS Jump if C == 1 Jump if no carry (if unsigned >=) JN Jump if N == 1 Jump if negative (No JP) JGE Jump if N == V Jump if zero or positive (if signed >=) JL Jump if N != V Jump if less than (if signed <) JMP Jump Jump unconditionally BYU CS 224 Assembler / Linker

10 Emulated Instructions
In addition to the 27 instructions defined by the MSP 430 ISA, there are 24 additional emulated instructions The emulated instructions make reading and writing code more easy, but do not have their own op-codes Emulated instructions are replaced automatically by native MSP 430 instructions There are no penalties for using emulated instructions. BYU CS 224 Assembler / Linker

11 Emulated Instructions
Mnemonic Operation Emulation Description Arithmetic instructions ADC(.B or .W) dst dst+Cdst ADDC(.B or .W) #0,dst Add carry to destination DADC(.B or .W) dst dst+Cdst (decimally) DADD(.B or .W) #0,dst Decimal add carry to destination DEC(.B or .W) dst dst-1dst SUB(.B or .W) #1,dst Decrement destination DECD(.B or .W) dst dst-2dst SUB(.B or .W) #2,dst Decrement destination twice INC(.B or .W) dst dst+1dst ADD(.B or .W) #1,dst Increment destination INCD(.B or .W) dst dst+2dst ADD(.B or .W) #2,dst Increment destination twice SBC(.B or .W) dst dst+0FFFFh+Cdst dst+0FFhdst SUBC(.B or .W) #0,dst Subtract source and borrow /.NOT. carry from dest. Program flow control BR dst dstPC MOV dst,PC Branch to destination DINT 0GIE BIC #8,SR Disable (general) interrupts EINT 1GIE BIS #8,SR Enable (general) interrupts NOP None MOV R3,R3 No operation RET @SPPC SP+2SP Return from subroutine BYU CS 224 Assembler / Linker

12 Emulated Instructions
Mnemonic Operation Emulation Description Program flow control INV(.B or .W) dst .NOT.dstdst XOR(.B or .W) #0(FF)FFh,dst Invert bits in destination RLA(.B or .W) dst CMSBMSB-1 LSB+1LSB0 ADD(.B or .W) dst,dst Rotate left arithmetically RLC(.B or .W) dst LSB+1LSBC ADDC(.B or .W) dst,dst Rotate left through carry NOP None MOV R3,R3 No operation Data instructions CLR(.B or .W) dst 0dst MOV(.B or .W) #0,dst Clear destination CLRC 0C BIC #1,SR Clear carry flag CLRN 0N BIC #4,SR Clear negative flag CLRZ 0Z BIC #2,SR Clear zero flag POP(.B or .W) dst @SPtemp SP+2SP tempdst MOV(.B or Pop byte/word from stack to destination SETC 1C BIS #1,SR Set carry flag SETN 1N BIS #4,SR Set negative flag SETZ 1Z BIS #2,SR Set zero flag TST(.B or .W) dst dst + 0FFFFh + 1 dst + 0FFh + 1 CMP(.B or .W) #0,dst Test destination BYU CS 224 Assembler / Linker

13 Quiz Pointers Given the memory contents to the right, what are the values for registers r4 and r5 after each instruction to the left is executed? Address Memory Assembly 0x8100 1 2 0x8102 3 4 0x8104 5 6 0x8106 7 8 0x8108 0x810a 0x8101 0x810c 0x810e 0x8103 0x8110 0x8112 0x8105 0x8114 0x8116 0x8107 tab1: .byte 1,2 .byte 3,4 .byte 5,6 .byte 7,8 tab2: .word tab1+0 .word tab1+1 .word tab1+2 .word tab1+3 .word tab1+4 .word tab1+5 .word tab1+6 .word tab1+7 Instructions r4 r5 mov.w #tab1,r4 mov.w #3,r4 mov.b tab1(r4),r5 mov.w tab2(r4),r5 add.w r4,r4 BYU CS 224 Assembler / Linker

14 Assembler

15 Assembler MSP430 Assembler An assembler outputs an object file
An assembler translates a program into machine code An assembly program is a text file containing assembly instructions, directives, macros, and comments Assembler Symbol Table input to a linker program BYU CS 224 Assembler / Linker 15

16 Assembler Coding Format
MSP430 Assembler Assembler Coding Format Assembler directives begin with a period (.) The ".cdecls" directive inserts a header file into your program. ;************************************************************************* ; CS 224 Lab 1 - blinky.asm: Software Toggle P1.0 ; ; Description: Toggle P1.0 by xor'ing P1.0 inside of a software loop. DELAY equ 0 .cdecls C,"msp430.h" ; MSP430 .text ; beginning of executable code start: mov.w #0x0400,SP ; init stack pointer mov.w #WDTPW|WDTHOLD,&WDTCTL ; stop WDT bis.b #0x01,&P1DIR ; set P1.0 as output mainloop: xor.b #0x01,&P1OUT ; toggle P1.0 mov.w #DELAY,r ; use R15 as delay counter delayloop: sub.w #1,r ; delay over? jnz delayloop ; n jmp mainloop ; y, toggle led .sect ".reset" ; MSP430 RESET Vector .word start ; start address .end Labels start in column 1 (case sensitive) Begin writing your assembly code after the ".text" directive. Label Operation Operands Comments Instructions are lower case and macros are UPPER CASE. The ".end" directive is the last line of your program. BYU CS 224 Assembler / Linker

17 Symbols / Labels Symbols Labels
Assembly Code Symbols / Labels Symbols Symbols are name/value pairs and stored in a symbol table. A symbol name is a string of up to 200 alphanumeric characters (A-Z, a-z, 0-9, $, and _), cannot contain embedded blanks, is case sensitive, and the first character cannot be a number. A symbol value is a label, constant, or substitution value. Symbols used as labels become symbolic addresses that are associated with locations in the program. Labels Labels are symbols. Labels begins in column 1 and is optionally followed by a colon. The value of a label is the current value of the Location Counter (address within program). A label on a line by itself is a valid statement. Labels used locally within a file must be unique. BYU CS 224 Assembler / Linker

18 Symbols / Labels Symbols Labels Name/value pairs
Assembly Code Symbols / Labels Symbols Name/value pairs Stored in a symbol table. Up to 200 alphanumeric characters (A-Z, a-z, 0-9, $, and _) No embedded blanks Case sensitive First character cannot be a number. A symbol value is a label, constant, or substitution value. Labels Labels are symbols. Labels begins in column 1 and is optionally followed by a colon. The value of a label is the current value of the Location Counter (address within program). A label on a line by itself is a valid statement. Labels used locally within a file must be unique. BYU CS 224 Assembler / Linker

19 Mnemonics / Operands Mnemonic Field Operand Field
Assembly Code Mnemonics / Operands Mnemonic Field The mnemonic field cannot start in column 1; if it does, it is interpreted as a label. The mnemonic field contains one of the following items: MSP430 instruction mnemonic (ie. ADD, MOV, JMP) Assembler directive (ie. .data, .list, .equ) Macro directive (ie. .macro, .var, .mexit) Macro invocation Operand Field The operand field follows the mnemonic field and optionally contains one or more operands. An operand may consist of: Symbols Constants Expressions (combination of constants and symbols) Operands are separated with commas BYU CS 224 Assembler / Linker 19

20 Constants / Expressions
Assembly Code Constants / Expressions Constants are maintained internally as a 32-bit, signed (2’s complement) or unsigned numbers. Constants are not sign extended. The pound sign precedes a constant in an instruction Decimal: decimal digits ranging from to (ie, 1000, ) Hexadecimal: up to 8 hexadecimal digits followed by ‘H’ (or ‘h’) or preceded by ‘0x’ (ie, 78h, 0x78) Binary: up to 32 binary digits followed by suffix B (or b) (ie. 0000b, B) An expression is a constant, a symbol, or a series of constants and symbols separated by arithmetic operators that evaluates to a single 32-bit number. to for signed values 0 to for unsigned values BYU CS 224 Assembler / Linker 20

21 Expressions / Operators
Assembly Code Expressions / Operators The precedence order of expression evaluation is Evaluate parenthesized expressions Evaluate operators according to precedence groups When parentheses and precedence groups do not determine the order of expression evaluation, the expressions are evaluated from left to right Group Operator Description 1 +, -, ~, ! Unary plus, minus, 1’s complement, logical NOT 2 *, /, % Multiplication, Division, Modulo 3 +, - Addition, Subtraction 4 <<, >> Shift left, Shift right 5 <, <=, >, >= Less than, Less than or equal to, Greater than, Greater than or Equal to 6 =[=], != Equal to, Not equal to 7 & Bitwise AND 8 ^ Bitwise exclusive OR (XOR) 9 | Bitwise OR BYU CS 224 Assembler / Linker 21

22 Assembler Directives Assembly directives are used to: Directives
Assembly Code Assembler Directives Assembly directives are used to: Create symbol table entries (.equ, .set, .cdecls). Select assembler sections (.sect, .bss, .text). Define values for memory locations (.byte, .word, .string). Specify the end of program (.end). ;******************************************************************************* ; CS/ECEn 124 Example Code .cdecls C,"msp430x22x4.h" ; include C header COUNT .equ 2000 ; .bss cnt,2 ; ISR counter .text ; Program reset start: mov.w #0x0400,SP ; Initialize stack pointer mov.w #WDT_MDLY_0_5,&WDTCTL ; Set Watchdog interval to ~0.5ms bis.w #LPM0+GIE,SR ; Enter LPM0 w/ interrupt jmp $ ; Loop forever; interrupts do all .sect ".reset" ; MSP430 RESET Vector .word start ; Power Up ISR .end Directives Current Location Counter BYU CS 224 Assembler / Linker

23 Assembly Style Guidelines
Assembly Code Assembly Style Guidelines Provide a program header, with author’s name, date, etc., and purpose of program. Start labels, opcode, operands, and comments in same column for each line. (Unless entire line is a comment.) Use comments to explain what each register does. Labels, symbols are case sensitive. Use meaningful symbolic names. Mixed upper and lower case for readability. ASCIItoBinary, InputRoutine, SaveR1 Provide comments between program sections. Each line must fit on the page -- no wraparound or truncations. BYU CS 224 Assembler / Linker

24 Quiz 6.2 What is an expression?
What is the difference between a symbol and a label? Can the name “add” be used as a label? What is the difference between a directive and a mnemonic? BYU CS 224 Assembler / Linker

25 Assembler Sections

26 Assembler Sections Assembler Sections A section is a block of code or data that occupies contiguous space in the memory map. Each section has its own Location Counter. The assembler assembles into the current section. There are two types of sections: Initialized sections containing data or code (modal) .sect .text Uninitialized sections reserving space in the memory map for uninitialized data (temporary) .bss .usect Object File Target Memory .bss var,2 RAM .usect "mySection" .text ROM (Flash) .sect "reset" BYU CS 224 Assembler / Linker

27 Assembler Sections Location Counter The Location Counter holds the relative memory position of an instruction within the current section. Each section has a location counter used to assign storage addresses to your program's statements. As the instructions of a source module are being assembled, the location counter keeps track of the current location in storage. A $ (dollar sign) can be used as an operand to an instruction to refer to the current value of the location counter. The assembler assembles into the current section. An initialized section directive instructs the assembler to stop assembling in the current section and begin assembling in the indicated section (modal). An uninitialized section directive does not end the current section, but simply escape from the current section temporarily. (Thus uninitialized directives .bss and .usect can appear anywhere in an initialized section without affecting its contents.) BYU CS 224 Assembler / Linker

28 Quiz 6.3 List the Location Counter values for the following:
.cdecls C,"msp430.h" ; include c header .bss cnt,2 ; WDT second counter .bss cat,4 .text ; program section start: mov.w #0x0400,SP ; set stack pointer mov.w #0x5a18,&WDTCTL ; set WD timer interval mov.w #0x00fa,&cnt ; 1 sec WD counter mov.b #0x01,&IE1 ; enable WDT interrupt bis.b #0x01,&P1DIR ; P1.0 output bis.w #0x0018,SR ; enable interrupts .bss dog,2 wdt_isr: xor.b #0x01,&P1OUT ; toggle P1.0 reti ; return from interrupt .sect ".int10" ; WDT vector section .word wdt_isr ; Watchdog ISR .sect ".reset" ; PUC vector section .word start ; RESET ISR .end BYU CS 224 Assembler / Linker

29 Assembly Process Assembly Process The assembler translates 1-to-1 assembly language instructions (.asm) into the machine language of the ISA (.obj) 1st Pass: store all labels/constants and their corresponding addresses/values in the symbol table Zero all Location Counters ($) For each non-empty line in the .text section: if line contains a label, add label and current LC to the symbol table if line contains an instruction, increment the LC accordingly Stop when .end directive is found. 2nd Pass: convert instructions to machine language, using information from symbol table Find the .text assembly directive and zero all Location Counters ($) For each executable assembly language statement: generate the corresponding machine language instruction resolve labels referenced in instructions using the symbol table increment LC for each instruction as in pass 1 output resulting machine code and program listing to output files BYU CS 224 Assembler / Linker

30 Common Assembler Directives
Reserves uninitialized bytes in RAM section (Does NOT change current section) Mnemonic and Syntax Description .bss symbol, size in bytes[, alignment] Reserves size bytes in the .bss (uninitialized data) section .sect "section name" Assembles into a named (initialized) section .text Assembles into the .text (executable code) section .byte value1[, ..., valuen] Initializes one or more successive bytes in the current section .string "string1"[, ..., "stringn"] Initializes one or more text strings .word value1[, ... , valuen] Initializes one or more 16-bit integers .align [size in bytes] Aligns the LC on a boundary specified by size in bytes; must be a power of 2; defaults to word (2 byte) .def symbol1[, ... , symboln] Identifies one or more symbols that are defined in current module and that can be used in other modules .include ["]filename["] Includes source statements from another file .ref symbol1[, ... , symboln] Identifies one or more symbols used in the current module that are defined in another module symbol .equ value Equates value with symbol symbol .set value .cdecls [options,] "filename" Share C headers between C and assembly code .end Ends program Changes to new section (New Location Counter) Fills (initializes) bytes in CURRENT section (Does NOT change section) Creates Name/Value symbol table entry (Does NOT effect any section Location Counter) BYU CS 224 Assembler / Linker

31 Linker Linker The Linker program "links" two files together according to their declared sections: BYU CS 224 Assembler / Linker

32 Library Routines Library Library routine invocation
Libraries Library Routines Library A set of routines for a specific domain application. Example: math, graphics, GUI, etc. Use the .ref directive to reference symbols defined outside a program. Library routine invocation Labels for the routines are defined as .def Each library routine contains its own symbol table. A linker resolves the external addresses before creating the executable image. Reports and unresolved symbols. BYU CS 224 Assembler / Linker

33 Linking Multiple Files
Libraries Linking Multiple Files .ref myFunc .ref sqrt .text … call #myFunc call #sqrt .end Source Module A Module A Object Symbol Table Assembler Module A Object Executable Image Linker .def myFunc .text myFunc: … ret .end Source Module B Module B Object Symbol Table Assembler Module B Object Math Library Symbol Table BYU CS 224 Assembler / Linker

34 Quiz 6.4 Create assembler and linker symbol table values for the following program: (Note: the linker loads the .text section at memory address 0xc000.) DELAY .equ 0 .text reset: mov.w #0x0400,SP mov.w #0x5a80,&0x0120 bis.b #0x01,&0x0022 mloop: xor.b #0x01,&0x0021 mov.w #DELAY,r15 dloop: dec.w r15 jnz dloop dlp2: dec.w r15 jnz dlp2 jmp mloop .sect ".reset" .word reset .end Symbol Name Assembler Value Resolved Linker BYU CS 224 Assembler / Linker

35 How to Code Assembler

36 How To Code Assembler… Understand the problem (obviously)
Coding Assembler How To Code Assembler… Understand the problem (obviously) Until you are comfortable in assembly, (and even afterwards), write out your solution in something familiar English Flowchart Pseudo-code Java, C, Ruby – the pseudo-code doesn’t really matter! Then, translate to assembler BYU CS 224 Assembler / Linker

37 Three Basic Constructs
Coding Assembler Three Basic Constructs BYU CS 224 Assembler / Linker

38 if-then-else if-then-else cmp.w #1,buzzerON ; jne myElse ;
Coding Assembler if-then-else if-then-else cmp.w #1,buzzerON ; jne myElse ; xor.b #0x20,&P4OUT ; bis.b #0x02,&P1OUT ; jmp myNext ; myElse: ; bic.b #0x02,&P1OUT ; ; myNext: ; if (buzzerON == 1) { pulse_buzzer(); turn_on_LED(); } else turn_off_LED(); BYU CS 224 Assembler / Linker

39 switch / case switch / case cmp.w #DOT,myByte ; switch (myByte)
Coding Assembler switch / case switch / case cmp.w #DOT,myByte ; jne sw_ ; call #do_dot ; jmp sw_end ; sw_01: cmp.w #DASH,myByte ; jne default ; call #do_dash ; ; default: ; sw_end: ; switch (myByte) { case DOT: do_dot(); break; case DASH: do_dash(); default: } BYU CS 224 Assembler / Linker

40 for-loop for-loop .bss i,2 ; mov.w #0,i ; for_ck: cmp.w #10,i ;
Coding Assembler for-loop for-loop .bss i, ; mov.w #0,i ; for_ck: cmp.w #10,i ; jge for_done ; call #do_dot ; call #delay ; call #do_dash ; add.w #1,i ; jmp for_ck ; for_done: ; int i; for(i=0; i<10; i++) { do_dot(); delay(); do_dash(); } BYU CS 224 Assembler / Linker

41 while while loop… TRUE .equ 1 .bss blink,2 ; mov.w #TRUE,blink ;
Coding Assembler while while loop… TRUE .equ 1 .bss blink, ; mov.w #TRUE,blink ; while_loop: ; cmp.w #0,blink ; jeq while_done ; call #LED_ON ; call #delay ; call #LED_OFF ; jmp while_loop ; while_done: ; #define TRUE 1 int blink = TRUE; while (blink) { LED_ON(); delay(); LED_OFF(); } BYU CS 224 Assembler / Linker

42 Quiz 6.5 Code the following C program in assembler: int i;
void func1(void) { ++i; return; } void func2(void) { i += 2; return; } void main(void) { for (i = 1; i < 10; i++) if (i < 5) func1(); } else func2(); BYU CS 224 Assembler / Linker

43 Systematic Decomposition
IDEA Step by Step Procedure Finiteness Must terminate. Definiteness Each step is precisely stated. Effective Computability Each step can be carried out. BYU CS 224 Assembler / Linker

44 Stepwise Refinement Also known as systematic decomposition.
Start with problem statement: “Write an assembler program to play the game of Simon using the LEDs and push button switches.” Decompose task into a few simpler subtasks. Decompose each subtask into smaller subtasks, and these into even smaller subtasks, etc.... until you get to the machine instruction level. Incrementally develop program and test, test, test… BYU CS 224 Assembler / Linker

45 Systematic Decomposition
Problem Statement Because problem statements are written in English, they are sometimes ambiguous and/or incomplete. How is the game played? How many LEDs start the game? Which switches and which LEDs? How long is an LED on or off? What happens when an error is made? What happens when a sequence is successfully reproduced? How is a new sequence started? … How do you resolve these issues? Ask the person who wants the problem solved, or Make a decision and document it. BYU CS 224 Assembler / Linker

46 Simon Example Incremental Development Pseudo-code Algorithm Problem
Systematic Decomposition Simon Example start: call #init_board newGame: call #new_game call #saveRandSeed mov.b #0xff,&success mov.w #TRYS-1,&trys tryLoop: tst.b &success jeq newGame inc.w &trys test: mov.w #0,r15 testLoop: cmp.w r15,&trys jge player call #getRand and.w #0x0003,r12 call #doLEDsTone inc.w r15 jmp testLoop: player: call #restoreRandSeed ... Incremental Development while (1) { new_game: { saveRandSeed; success = TRUE; trys = TRYS-1; } while(success) { doSequence: { restoreRandSeed; trys++; for (i=0; i<trys; i++) { getRand; doLEDsTone; doPlayer: { getSwitch; if (getRand  switch) { success = FALSE; break; doResults: { if (success) outSuccess; else outRaspberry; Pseudo-code Setup new game. Output random sequence of tones and LEDs. Reset sequence. Get and compare player’s response. Output results and restart game w/new sequence. Init Simon board. Algorithm “Play the game of Simon using the LEDs and push button switches.” Problem BYU CS 224 Assembler / Linker

47 BYU CS 224 Assembler / Linker