C/C++ Users Group Library 1996 July

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A Comparison of =========================================================== MM MM IIIIIII CCCC RRRRRR OOO CCCC M M M M I C C R R O O C C M M M I C R R O O C M M I C RRRRRR O O ----- C M M I C R R O O C M M I C C R R O O C C M M IIIIIII CCCC R R OOO CCCC =========================================================== A N D =========================================================== SSSSS MM MM A L L CCCC S S M M M M A A L L C C S M M M A A L L C SSSSS M M A A L L ----- C S M M AAAAAAA L L C S S M M A A L L C C SSSSS M M A A LLLLLLL LLLLLLL CCCC =========================================================== Copyright 1990-1994 Dave Dunfield All rights reserved MICRO-C .vs. SMALL-C Page: 1 1. INTRODUCTION The most common reaction of people hearing about DDS MICRO-C for the first time is something like "Humph... Another version of the old SMALL-C compiler". This couldn't be further from the truth. MICRO-C IS NOT SMALL-C!!! MICRO-C is a completely new implementation of a 'C' compiler suitable for use on very small systems. It offers several advantages over SMALL-C: - It was designed from the ground up to be easily portable to different processors & computer platforms. Code generators are available for 8080, 8051, 80x86, 8096, 6809, 68HC11 and 68HC16 cpu's, and an entire section of the manual is devoted to porting the compiler. Although SMALL-C claims to be easily portable, much of it's arcitecture is oriented toward the original 8080 processor. For an example of how this affects the compiler, compare the code generated by the 8086 version of SMALL-C to reference stack (auto) variables to that produced by MICRO-C. - It is a more complete implementation of the 'C' language, see the features comparison later in this document. - It produces faster, more compact code. See the benchmark results later in this document. - MICRO-C employs a fully tokenized parser, allowing statement analysis to be performed on 16 bit "tokens" instead of text strings as is done in SMALL-C. This results in MUCH faster compilation. - Although it is higher in functionality than SMALL-C, the MICRO-C compiler is much smaller than SMALL-C (Nearly half the size). This allows it to run on very small computer systems. 2. DETAILED COMPARISON OF COMPILERS The following pages contain a detailed comparison of the SMALL-C version 2 compiler, and MICRO-C. MICRO-C .vs. SMALL-C Page: 2 2.1 'C' Implementation = Data Types ===========+ SMALL-C V1 + SMALL-C V2 + MICRO-C + int | Yes | Yes | Yes | char | Yes | Yes | Yes | unsigned int | No | No | Yes | unsigned char | No | No | Yes | pointers | Yes | Yes | Yes | pointers to pointers | No | No | Yes | structs & unions | No | No | Yes | Single dimension arrays | Yes | Yes | Yes | Multi dimension arrays | No | No | Yes | Arrays of pointers | No | No | Yes | Arrays of structs | No | No | Yes | Typecast | No | No | Yes | sizeof | No | No | Yes | Static globals & locals | No | No | Yes | = Control Structures ===+ SMALL-C V1 + SMALL-C V2 + MICRO-C + if/else | Yes | Yes | Yes | while | Yes | Yes | Yes | do/while | No | Yes | Yes | for | No | Yes | Yes | switch/case | No | Yes | Yes | goto | No | Yes | Yes | Conditional Expressions | No | Yes | Yes | Inline assembler | Yes | Yes | Yes | = Pre-Processor ========+ SMALL-C V1 + SMALL-C V2 + MICRO-C + #define (basic) | Yes | Yes | Yes | #define (Parameterized) | No | No | Yes | #define (Multi-line) | No | No | Yes | #undef | No | No | Yes | #include (single level) | Yes | Yes | Yes | #include (nested) | No | Yes | Yes | #ifdef/#ifndef | No | Yes | Yes | = Misc features ========+ SMALL-C V1 + SMALL-C V2 + MICRO-C + Optimization | No | Yes | Yes | Multiple memory models | No | No | Yes | Make/touch utility | No | No | Yes | Source linker | No | No | Yes | 68HC08 code generator | No | No | Yes | 6809 code generator | No | No | Yes | 68HC11 code generator | No | No | Yes | 68HC16 code generator | No | No | Yes | 8080 code generator | Yes | Yes | Yes | 8051 code generator | No | No | Yes | 8086 code generator | No | Yes | Yes | 8096 code generator | No | No | Yes | Complete standard lib | No | Yes | Yes | Interrupt serial I/O | No | No | Yes | Windowing library | No | No | Yes | TSR support | No | No | Yes | MICRO-C .vs. SMALL-C Page: 3 2.2 Generated code quality To test the actual performace of code generated by MICRO-C against code generated by SMALL-C, I used this "Sieve of Eratosthenes" prime number generator program, taken from the BYTE benchmarks: /* * The classic "Sieve of Eratosthenes" prime number program. * from BYTE, January 1983. */ #include <stdio.h> #include "timer.c" /* The timer subroutines */ #define SIZE 8190 #define LOOP 100 #define TRUE 1 #define FALSE 0 char flags [SIZE + 1]; main() { int i, prime, k, count, iter; printf("BYTE Sieve Benchmark - %d iterations\n",LOOP); /* Start timer and execute loop */ startimer(timestamp); for(iter = 1; iter <= LOOP; ++iter) { count = 0; /* prime counter */ for(i = 0; i <= SIZE; ++i) /* set all flags true */ flags [i] = TRUE; for(i = 0; i <= SIZE; ++i) { if(flags [i]) { /* found a prime */ prime = i + i + 3; /* twice index + 3 */ /* printf ("\n%d", prime); */ for(k = i + prime; k <= SIZE; k+= prime) flags [k] = FALSE; /* kill all multiple */ ++count; } } } /* primes found */ elapsed(timestamp); /* Calculate time taken */ /* Report results */ printf("%d primes.\n\n", count); /* primes found on 100th pass */ printf("Elapsed time: %02d:%02d:%02d.%02d\n", timestamp[1], timestamp[0], timestamp[3], timestamp[2]); } MICRO-C .vs. SMALL-C Page: 4 2.3 Speed of compilation To show the relative compilation times, I wrote this simple MICRO-C program, using the timing routines shown below, to execute the compilers & report the time taken: #include <stdio.h> #include "timer.c" /* The timer subroutines */ main() { startimer(timestamp); system("CC SIEVE"); /* Execute the SMALL-C compiler */ elapsed(timestamp); printf("Elapsed time: %02d:%02d:%02d.%02d\n\n", timestamp[1], timestamp[0], timestamp[3], timestamp[2]); startimer(timestamp); system("MCC SIEVE.C SIEVE.ASM");/* Execute the MICRO-C compiler */ elapsed(timestamp); printf("Elapsed time: %02d:%02d:%02d.%02d\n", timestamp[1], timestamp[0], timestamp[3], timestamp[2]); } NOTE: The results from the above program will include the time taken to load the compilers. To minimize this, all tests were run from a RAMdisk. This eliminates disk seek time, and reduces load time to the speed of a memory to memory copy. MICRO-C .vs. SMALL-C Page: 5 2.4 Timing the tests These subroutines were used to time the programs, using the MS-DOS internal clock which has a resolution of 1/100 of a second: char timestamp[4]; /* Stores initial timestamp */ /* * Record system time for later calculation */ startimer() asm { MOV AH,2CH ; Get time function INT 21H ; Ask DOS MOV SI,4[BP] ; Get pointer to timestamp MOV [SI],CX ; Record hours & minites MOV 2[SI],DX ; Record seconds & hundreds } /* * Calculate elapsed time since timestamp recorded */ elapsed() asm { MOV AH,2CH ; Get time function INT 21H ; Ask DOS MOV SI,4[BP] ; Pointer to timestamp SUB DL,2[SI] ; Convert 100ths JNC ELAP1 ; No borrow ADD DL,100 ; Re-adjust DEC DH ; Reduce seconds ELAP1: MOV 2[SI],DL ; Save elapsed hundreds SUB DH,3[SI] ; Convert seconds JNS ELAP2 ; No borrow ADD DH,60 ; Re-adjust DEC CL ; Reduce minites ELAP2: MOV 3[SI],DH ; Save elapsed seconds SUB CL,[SI] ; Convert minites JNS ELAP3 ; No borrow ADD CL,60 ; Re-adjust DEC CH ; Adjust hours ELAP3: MOV [SI],CL ; Save elapsed minites SUB CH,1[SI] ; Convert hours MOV 1[SI],CH ; Save elapsed hours } MICRO-C .vs. SMALL-C Page: 6 2.5 Test results After compiling the programs, I ran the various tests on a standard 8-Mhz IBM PC/AT, with these results: E:\>dir Volume in drive E is VDISK V3.3 Directory of E:\ CC EXE 40626 4-27-93 /* SMALL-C compiler */ MCC COM 24154 4-27-93 /* MICRO-C compiler */ TIMER C 1094 4-27-93 /* The timer subroutines */ TIMECOMP C 527 4-27-93 /* The compiler timer */ SIEVE C 1149 4-27-93 /* The test program */ SIEVE-S EXE 16946 4-27-93 /* SMALL-C produced this */ SIEVE-M COM 1744 4-27-93 /* MICRO-C produced this */ TIMECOMP COM 1908 4-27-93 /* Executable compiler timer */ 8 File(s) 430080 bytes free E:\>sieve-s /* The SMALL-C version: 1 min, 28.98 secs */ BYTE Sieve Benchmark - 100 iterations 1899 primes. Elapsed time: 00:01:28.98 E:\>sieve-m /* The MICRO-C version: 0 min, 40.43 secs */ BYTE Sieve Benchmark - 100 iterations 1899 primes. Elapsed time: 00:00:40.43 E:\> **NOTE: Before running TIMECOMP, I created a "generic" STDIO.H file which was suitable for both compilers. E:\>timecomp /* Times to compile the program */ Small-C Compiler, Version 2.1, (Rev. 75) Copyright 1982, 1983, 1985 J. E. Hendrix Elapsed time: 00:00:04.72 /* SMALL-C 4.72 secs */ MICRO-C Compiler Copyright 1988-1993 Dave Dunfield All rights reserved. Elapsed time: 00:00:01.15 /* MICRO-C 1.15 secs */ E:\> MICRO-C .vs. SMALL-C Page: 7 3. OTHER ADVANTAGES OF MICRO-C In addition to being a superiour and more portable compiler, The MICRO-C package also offers these advantages: 3.1 Utilities MICRO-C Comes with the following utilities (all with complete MICRO-C source code): CC - Command Coordinator, combines pre-processor, compiler, optimizer, assembler and linker into a single command. Command line parameters allow very flexible operation. MAKE - Automates building of larger (multi module) programs. TOUCH - Set timestamp of file to current or specified date. (Used with MAKEs dependancy checking) SLINK - Source LINKer, Allows pre-compiled (assembler) source to be kept in a library and included as needed to resolve external references. Useful when MICRO-C is used as cross compiler for systems not supporting an object linker. SLIB - Utility for updating and maintaining a source library. SINDEX - Automatically indexes a source library for use by SLINK. SCONVERT- Converts assembly language source for use by SLINK. EXE2BIN - Converts MS-DOS EXE files to a binary image, useful for users of later versions of DOS which no longer include this utility. MCP - The MICRO-C Pre-processor MCC - The MICRO-C Compiler MCO - The MICRO-C Optimizer MICRO-C .vs. SMALL-C Page: 8 3.2 Example Programs MICRO-C comes with the following archives of example programs (all with complete MICRO-C source code): CUTIL: 'C' utilities & related programs CCREF - 'C' source cross referencing program COMEXT - Extract comments from 'C' sources CVTCOM - Convert C++ '//' comments to '/* */' OBSCURE - Make 'C' program un-readable (but it still compiles) PPC - Pretty Printer for 'C' (source formatter) SHELL - Command line / interactive shell program DOSUTIL: DOS utilities ANYFILE - Set ERRORLEVEL on file matching patterns BOOTMENU - "boot" menu, allowing different AUTOEXEC and CONFIG files CALC - A TSR programmers (HEX/DECIMAL) calculator CAN - Automatically append arguments to ".COM" files CHAINSAW - Remove an entire directory tree CHATTR - Change attributes of DOS files CMOS - Read/Write/Verify CMOS RAM from/to/with disk file COMCHK - Checksum .COM file every time it runs CSET - TSR map of IBM PC character set DIFF - Displays differences between text files DUMP - Hex/Octal/ASCII file dump utility EQUIP - Display hardware installed in PC GREP - Like unix "GREP" search utility HEM - Hardware Exception Monitor TSR to trap unexpected ints HEXED - Screen oriented Hex file editor LZC - Laser commander TSR to control HP compatible printers MEMSAVE - Saves memory image to file MTERM - Tiny (10k!) TSR ANSI terminal with XMODEM OFF - Screen saver PARK - Configurable hard disk parking utility PCD - PC "countdown" timer RETAB - Retabulates files to different TAB stops SCRUB - Utility for cleaning floppy drives SHOWEXE - Displays information about a .EXE file SIZE - Show file(s) exact size and number of lines STUFF - Stuffs keycodes into the keyboard buffer TFB - TSR File Browser TIMEIT - Time execution of other DOS commands TR - Like unix TR (translate) command TYPE4 - Display files with tabs at 4 character intervals VALIDATE - PD ver of McAfee's validate. Verify files with two CRC's LAPTALK: A small (20K) but powerful comms pogram LAPTALK - A terminal program with script interpreter XMODEM - External file transfer program MICROCAD: A VGA drawing program MICROCAD - Mouse based drawing program MCPRINT - Prints MICROCAD files on Laserjet or Epson printers MCDRAW - Minimal routines to display MICROCAD file in other pgms FE - Font Editor MICRO-C .vs. SMALL-C Page: 9 MISC: Other misc. programs ASM86 - 8086 assembler BASIC - A simple BASIC interpreter BIGNUM - Add/Sub/Mul/Div/Mod very large numbers BITARRAY - Example of using an array of bits. BJ - Blackjack (21) game BYTESWAP - Example of using UNION's CASTLE - A large text based "adventure" game FIBO - Calculates a fibonacci series FORTUNE - A "fortune cookie" - Displays random quotation HANOI - Solves "towers of hanoi" on screen HELLO - Standard 'C' demo program HFTEXT - Text compressor using Huffman encoding KIDSMENU - Colorful mouse/keyboard based menuing system for kids KMEDIT - Editor for kids menu database LONGCALC - A "long" (32 BIT) desk calculator MDCFS - Minimal DOS compatible File System OBFUSC - Example of how NOT to write 'C' PRIME - Calculates prime numbers PRIME1 - Another prime number calculator PTR2FUNC - Demo's use of pointers to functions RAIN - Makes characters "fall" off the screen RDC - Another text compression program RLTEXT - Text compression using run length encoding ROBOFACE - Draws a "robot face" SELFDUP - A self-replicating 'C' program! TEXTNUM - Converts numbers to text equivalent TTT3D - 3 dimensional tic-tac-toe WINDEMO - Demonstrates MICRO-C windowing MICRO-C .vs. SMALL-C TABLE OF CONTENTS Page 1. INTRODUCTION 1 2. DETAILED COMPARISON OF COMPILERS 1 2.1 'C' Implementation 2 2.2 Generated code quality 3 2.3 Speed of compilation 4 2.4 Timing the tests 5 2.5 Test results 6 3. OTHER ADVANTAGES OF MICRO-C 7 3.1 Utilities 7 3.2 Example Programs 8