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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 1990,1991 Dave Dunfield All rights reserved MICRO-C .vs. SMALL-C Page: 1 1. INTRODUCTION The most common reaction of people hearing about 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. Sample code generators are included for 8080, 8051, 80x86, 8096, 6809 and 68HC11 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 | Single dimension arrays | Yes | Yes | Yes | Multi dimension arrays | No | No | Yes | arrays of pointers | No | No | Yes | Typecast | No | No | Yes | sizeof | 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 | 6809 code generator | No | No | Yes | 68HC11 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 | ========================+==================================== Library features | SMALL-C V1 | SMALL-C V2 | MICRO-C | ------------------------+------------------------------------ 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 9-10-90 /* SMALL-C compiler */ MCC COM 22316 9-10-90 /* MICRO-C compiler */ TIMER C 1094 9-10-90 /* The timer subroutines */ TIMECOMP C 527 9-10-90 /* The compiler timer */ SIEVE C 1149 9-10-90 /* The test program */ SIEVE-S EXE 16946 9-10-90 /* SMALL-C produced this */ SIEVE-M COM 1651 9-10-90 /* MICRO-C produced this */ TIMECOMP COM 1924 9-10-90 /* Executable compiler timer */ 8 File(s) 301056 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: 1 min, 4.59 secs */ BYTE Sieve Benchmark - 100 iterations 1899 primes. Elapsed time: 00:01:04.59 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 2.0 Compiler Copyright 1988,1990 Dave Dunfield All rights reserved. Elapsed time: 00:00:01.32 /* MICRO-C 1.32 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 example programs (all with complete MICRO-C source code): ASM86.C An 8086 assembler BASIC.C A simple BASIC interpreter CALC.C A pop-up (TSR) calculator for programmers CASTLE.C A large "adventure" game CHATTR.C Chenges file attributes COMEXT.C Extracts comment from 'C' programs CSET.C A pop-up (TSR) PC character set CVTCOM.C Convert C++ style '//' comments to C's '/* - */' DUMP.C A HEX/OCTAL file dump utility EQUIP.C Displays equipment installed in your PC FIBO.C Calculates a fibonacci series FORTUNE.C Displays a "fortune cookie" message every time it is run GREP.C Unix like "grep" command from DECUS HANOI.C Solves the "towers of hanoi" program on screen HELLO.C Standard 'C' demo program HEM.C Traps hardware fault interrupts HEXED.C A full-screen hex file editor HFTEXT.C Simple Huffman encoded for text files INSTALL.C The Micro-Install program LZC.C Laser Commander - pop-up (TSR) control for laser printer MTERM.C A pop-up (TSR) ANSI terminal with XMODEM OBSCURE.C Makes a 'C' program un-readable (it still compiles) PPC.C Pretty-Printer for C PRIME.C Calculates prime numbers RLTEXT.C Simple Runn Length encoded for text files ROBOFACE.C Draws a robot face on your BC screen TEXTNUM.C Displays text equivalent of numbers TIMEIT.C Time the execution of another command TR.C Unix like "tr" command TTT3D.C Three-Dimensional Tic-Tac-Toe TYPE4.C Display a file with tabs at 4 character intervals VALIDATE.C PD version McAfee's validate program, uses dual CRC's WINDEMO.C MICRO-C window demonstration program 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