SIC/XE初探---Assembler和Linker

　　今晚彷佛又找到了刚学编译原理的时，想起了那时写出词法分析器以及到后面利用yacc等工具进行自动机的兴奋和喜悦。不过和学长们，失败的是我编译原理是在刀斧手-孔老师手下以高出2分的危险度过，62分而已。

 

　　来静宜学习上最大的阻力应该就是这门功课了，英语的课本，陌生的上课环境，计算机术语上的差异，以及这门功课本身的抽象和复杂，都让我有些吃力。还好，现在有了初探，有了很强烈的兴趣。

 

　　以下的代码是用c写出来的SIC/XE的ASSEMBLER文件。编译生成的EXE文件在CMD下打开后，输入ASM文件所在就能翻译成Object Code。不得不说很激动。关于C++文件和ASM文件待以后来完全弄懂。当初词法分析器不也是这么搞定的么，哈哈……

 

　　Sic.cpp

　　#include <stdio.h> #include <stdlib.h> #include <string.h> #include <malloc.h> /***************************** DECLERATE VARIABLE ****************************/ typedef struct OperationCodeTable { char Mnemonic[8]; char Format; unsigned short int ManchineCode; }SIC_OPTAB; typedef struct SymbolTable { char Label[10]; int Address; }SIC_SYMTAB; typedef struct IntermediateRecord{ unsigned short int LineIndex; unsigned short int Loc; unsigned long int ObjectCode; char LabelField[32]; char OperatorField[32]; char OperandField[32]; }IntermediateRec; int Counter; int LOCCTR[100]; int LocctrCounter = 0; int ProgramLen; int Index; int j; int ManchineCode; int SymtabCounter = 0; int start_address; int program_length; int ArrayIndex = 0; unsigned short int FoundOnSymtab_flag = 0; unsigned short int FoundOnOptab_flag = 0; char Buffer[256]; char Label[32]; char Mnemonic[32]; char Operand[32]; SIC_SYMTAB SYMTAB[20]; IntermediateRec* IMRArray[100]; static SIC_OPTAB OPTAB[]= { { "ADD", '3', 0x18}, { "AND", '3', 0x40}, { "COMP", '3', 0x28}, { "DIV", '3', 0x24}, { "J", '3', 0x3C}, { "JEQ", '3', 0x30}, { "JGT", '3', 0x34}, { "JLT", '3', 0x38}, { "JSUB", '3', 0x48}, { "LDA", '3', 0x00}, { "LDCH", '3', 0x50}, { "LDL", '3', 0x08}, { "LDX", '3', 0x04}, { "MUL", '3', 0x20}, { "OR", '3', 0x44}, { "RD", '3', 0xD8}, { "RSUB", '3', 0x4C}, { "STA", '3', 0x0C}, { "STCH", '3', 0x54}, { "STL", '3', 0x14}, { "STSW", '3', 0xE8}, { "STX", '3', 0x10}, { "SUB", '3', 0x1C}, { "TD", '3', 0xE0}, { "TIX", '3', 0x2C}, { "WD", '3', 0xDC}, }; /****************************** DFINATE FUNCTION *****************************/ char* ReadLabel(){ j = 0;//zeroing while (Buffer[Index] != ' ' && Buffer[Index] != '/t' && Buffer[Index] != '/n') Label[j++] = Buffer[Index++]; Label[j] = '/0'; return(Label); } void SkipSpace(){ while (Buffer[Index] == ' ' || Buffer[Index] =='/t') Index++; } char* ReadOprator(){ j = 0;//zeroing while(Buffer[Index] != ' ' && Buffer[Index] != '/t' && Buffer[Index] != '/n') Mnemonic[j++] = Buffer[Index++]; Mnemonic[j] = '/0'; return(Mnemonic); } char* ReadOperand(){ j = 0;//zeroing while(Buffer[Index] != ' ' && Buffer[Index] != '/t' && Buffer[Index] != '/n') Operand[j++] = Buffer[Index++]; Operand[j] = '/0'; return(Operand); } void RecordSymtab(char* label){ strcpy(SYMTAB[SymtabCounter].Label,label); SYMTAB[SymtabCounter].Address = LOCCTR[LocctrCounter-1]; SymtabCounter++; } int SearchSymtab(char* label){ FoundOnSymtab_flag = 0; for (int k= 0; k<=SymtabCounter; k++) { if (!strcmp(SYMTAB[k].Label,label)){ FoundOnSymtab_flag = 1; return (FoundOnSymtab_flag); break; } } return (FoundOnSymtab_flag); } int SearchOptab(char * Mnemonic){ int size = sizeof(OPTAB)/sizeof(SIC_OPTAB); FoundOnOptab_flag = 0; for(int i=0;i<size;i++){ if(!strcmp(Mnemonic,OPTAB[i].Mnemonic)){ Counter = i; FoundOnOptab_flag = 1; break; } } return (FoundOnOptab_flag); } int StrToDec(char* c){ int dec_num = 0; char temp[10]; strcpy(temp,c); int len = strlen(c); for (int k = len-1, l = 1; k>=0; k--) { dec_num = dec_num+int(temp[k]-'0')*l; l = l*10; } return (dec_num); } int StrToHex(char* c) { int hex_num = 0; char temp[10]; strcpy(temp, c); int len = strlen(temp); for (int k = len-1, l = 1; k >=0; k--) { if (temp[k]>='0' && temp[k]<='9') hex_num = hex_num + int (temp[k]-'0')*l; else if (temp[k]>='A' && temp[k]<='F') hex_num = hex_num + int (temp[k]-'A'+10)*l; else if (temp[k]>='a' && temp[k]>='f') hex_num = hex_num + int (temp[k]-'a'+10)*l; else ; l = l*16; } return (hex_num); } int ComputeLen(char* c){ unsigned int b; char len[32]; strcpy(len,c); if (len[0] =='C' || len[0] =='c' && len[1] =='/''){ for (b = 2; b<=strlen(len); b++){ if (len[b] == '/''){ b -=2; break; } } } if (len[0] =='X' || len[0] =='x' && len[1] =='/'') b = 1; return (b); } void CreateProgramList(){ int loop; FILE *fptr_list; fptr_list = fopen("sic.list","w"); if (fptr_list == NULL) { printf("ERROE: Unable to open the sic.list./n"); exit(1); } fprintf(fptr_list, "%-4s/t%-10s%-10s%-10s/t%s/n", "LOC", "LABEL", "OPERATOR", "OPERAND", "OBJECT CODE"); for (loop = 0; loop<ArrayIndex; loop++) { if (!strcmp(IMRArray[loop]->OperatorField,"START") || !strcmp(IMRArray[loop]->OperatorField,"RESW") || !strcmp(IMRArray[loop]->OperatorField,"RESB") || !strcmp(IMRArray[loop]->OperatorField,"END")) fprintf(fptr_list, "%04x/t%-10s%-10s%-10s/n", IMRArray[loop]->Loc, IMRArray[loop]->LabelField, IMRArray[loop]->OperatorField, IMRArray[loop]->OperandField); else fprintf(fptr_list, "%04x/t%-10s%-10s%-10s/t%06x/n", IMRArray[loop]->Loc, IMRArray[loop]->LabelField, IMRArray[loop]->OperatorField, IMRArray[loop]->OperandField, IMRArray[loop]->ObjectCode); } fclose(fptr_list); } void CreateObjectCode(){ int first_address; int last_address; int temp_address; int temp_objectcode[30]; int first_index; int last_index; int x,xx; int loop; char temp_operator[12][10]; char temp_operand[12][10]; FILE *fptr_obj; fptr_obj = fopen("sic.obj","w"); if (fptr_obj == NULL) { printf("ERROE: Unable to open the sic.obj./n"); exit(1); } printf("Creating Object Code.../n/n"); loop = 0; if (!strcmp(IMRArray[loop]->OperatorField, "START")) { printf("H%-6s%06x%06x/n",IMRArray[loop]->LabelField, start_address, program_length); fprintf(fptr_obj,"H^%-6s^%06x^%06x/n",IMRArray[loop]->LabelField, start_address, program_length); loop++; } while(1) { first_address = IMRArray[loop]->Loc; last_address = IMRArray[loop]->Loc + 27; first_index = loop; for (x = 0, temp_address = first_address ; temp_address<=last_address; loop++) { if (!strcmp(IMRArray[loop]->OperatorField, "END")) break; else if (strcmp(IMRArray[loop]->OperatorField, "RESB") && strcmp(IMRArray[loop]->OperatorField, "RESW")) { temp_objectcode[x] = IMRArray[loop]->ObjectCode; strcpy(temp_operator[x], IMRArray[loop]->OperatorField); strcpy(temp_operand[x], IMRArray[loop]->OperandField); last_index = loop+1; x++; } else ; temp_address = IMRArray[loop+1]->Loc; } printf("T%06x%02x", first_address, (IMRArray[last_index]->Loc - IMRArray[first_index]->Loc)); fprintf(fptr_obj, "T^%06x^%02x", first_address, (IMRArray[last_index]->Loc - IMRArray[first_index]->Loc)); for (xx = 0; xx<x; xx++) { if ((strcmp(temp_operator[xx], "BYTE")==0) && (temp_operand[xx][0]=='X' || temp_operand[xx][0]=='x')){ printf("%02x", temp_objectcode[xx]); fprintf(fptr_obj, "^%02x", temp_objectcode[xx]); } else{ printf("%06x", temp_objectcode[xx]); fprintf(fptr_obj, "^%06x", temp_objectcode[xx]); } } printf("/n"); fprintf(fptr_obj,"/n"); if (!strcmp(IMRArray[loop]->OperatorField, "END")) break; } printf("E%06x/n/n", start_address); fprintf(fptr_obj, "E^%06x/n/n", start_address); fclose(fptr_obj); } /******************************* MAIN FUNCTION *******************************/ void main (void) { FILE* fptr; char filename[10]; char label[32]; char opcode[32]; char operand[32]; int loc = 0; int line = 0; int loop; int is_empty_line; int is_comment; int loader_flag = 0; printf(" ******************************************************************************/n"); printf(" * Program: SIC ASSEMBYER */n"); printf(" * */n"); printf(" * Procedure: */n"); printf(" * - Enter file name of source code. */n"); printf(" * - Do pass 1 process. */n"); printf(" * - Do pass 2 process. */n"); printf(" * - Create /"program list/" data on sic.list.(Use Notepad to read this file) */n"); printf(" * - Create /"object code/" data on sic.obj.(Use Notepad to read this file) */n"); printf(" * - Also output object code to standard output device. */n"); printf(" ******************************************************************************/n"); printf("/nEnter the file name you want to assembly (sic.asm):"); scanf("%s",filename); fptr = fopen(filename,"r"); if (fptr == NULL) { printf("ERROE: Unable to open the %s file./n",filename); exit(1); } /********************************** PASS 1 ***********************************/ printf("Pass 1 Processing.../n"); while (fgets(Buffer,256,fptr) != NULL) { is_empty_line = strlen(Buffer); Index = 0; j = 0; strcpy(label,ReadLabel()); if (Label[0] == '.') is_comment = 1; else is_comment = 0; if (is_empty_line>1 && is_comment!=1) { Index = 0; j = 0; IMRArray[ArrayIndex] = (IntermediateRec*)malloc(sizeof(IntermediateRec));/* [A] */ IMRArray[ArrayIndex]->LineIndex = ArrayIndex; strcpy(label,ReadLabel()); strcpy(IMRArray[ArrayIndex]->LabelField,label); SkipSpace(); if (line == 0) { strcpy(opcode,ReadOprator()); strcpy(IMRArray[ArrayIndex]->OperatorField,opcode);/* [A] */ if (!strcmp(opcode,"START")) { SkipSpace(); strcpy(operand,ReadOperand()); strcpy(IMRArray[ArrayIndex]->OperandField, operand);/* [A] */ LOCCTR[LocctrCounter] = StrToHex(operand); start_address = LOCCTR[LocctrCounter]; } else { LOCCTR[LocctrCounter] = 0; start_address = LOCCTR[LocctrCounter]; } } else { strcpy(opcode,ReadOprator()); strcpy(IMRArray[ArrayIndex]->OperatorField,opcode); SkipSpace(); strcpy(operand,ReadOperand()); strcpy(IMRArray[ArrayIndex]->OperandField,operand); if (strcmp(opcode,"END")) { if (label[0] != '/0') { if (SearchSymtab(label)) { fclose(fptr); printf("ERROE: Duplicate Symbol/n"); FoundOnSymtab_flag = 0; exit(1); } RecordSymtab(label); } if (SearchOptab (opcode)) LOCCTR[LocctrCounter] = loc + int (OPTAB[Counter].Format-'0'); else if (!strcmp(opcode,"WORD")) LOCCTR[LocctrCounter] = loc + 3; else if (!strcmp(opcode,"RESW")) LOCCTR[LocctrCounter] = loc + 3 * StrToDec(operand); else if (!strcmp(opcode,"RESB")) LOCCTR[LocctrCounter] = loc + StrToDec(operand); else if (!strcmp(opcode,"BYTE")) LOCCTR[LocctrCounter] = loc + ComputeLen(operand); else{ fclose(fptr); printf("ERROE: Invalid Operation Code/n"); exit(1); } } } loc = LOCCTR[LocctrCounter]; IMRArray[ArrayIndex]->Loc = LOCCTR[LocctrCounter-1]; LocctrCounter++; ArrayIndex++; } FoundOnOptab_flag = 0; line += 1; } program_length = LOCCTR[LocctrCounter-2]- LOCCTR[0]; /********************************** PASS 2 ***********************************/ printf("Pass 2 Processing.../n"); unsigned long inst_fmt;// unsigned long inst_fmt_opcode; unsigned long inst_fmt_index; unsigned long inst_fmt_address; for (loop = 1; loop<ArrayIndex; loop++){ inst_fmt_opcode = 0; inst_fmt_index = 0; inst_fmt_address = 0; strcpy(opcode,IMRArray[loop]->OperatorField); if (SearchOptab(opcode)){ inst_fmt_opcode = OPTAB[Counter].ManchineCode; inst_fmt_opcode <<=16; IMRArray[loop]->ObjectCode = inst_fmt_opcode; strcpy(operand,IMRArray[loop]->OperandField); if (operand[strlen(operand)-2] == ',' && operand[strlen(operand)-1] == 'X'){ inst_fmt_index = 0x008000; operand[strlen(operand)-2] = '/0'; } else inst_fmt_index = 0x000000; for(int search_symtab = 0; search_symtab<SymtabCounter; search_symtab++){ if(!strcmp(operand, SYMTAB[search_symtab].Label)) inst_fmt_address = (long)SYMTAB[search_symtab].Address; } inst_fmt = inst_fmt_opcode + inst_fmt_index + inst_fmt_address; IMRArray[loop]->ObjectCode = inst_fmt; } else if (!strcmp(opcode, "WORD")){ strcpy(operand,IMRArray[loop]->OperandField); IMRArray[loop]->ObjectCode = StrToDec(operand); } else if (!strcmp(opcode,"BYTE")){ strcpy(operand,IMRArray[loop]->OperandField); IMRArray[loop]->ObjectCode = 0; if(operand[0]=='C' || operand[0]=='c' && operand[1]=='/''){ for (int x = 2; x<=int(strlen(operand)-2); x++){ IMRArray[loop]->ObjectCode=IMRArray[loop]->ObjectCode + (int)operand[x]; IMRArray[loop]->ObjectCode<<=8; } } if(operand[0]=='X' || operand[0]=='x' && operand[1]=='/''){ char *operand_ptr; operand_ptr = &operand[2]; *(operand_ptr+2)='/0'; for (int x=2; x<=int(strlen(operand)-2); x++){ IMRArray[loop]->ObjectCode=IMRArray[loop]->ObjectCode + StrToHex(operand_ptr); IMRArray[loop]->ObjectCode<<=8; } } IMRArray[loop]->ObjectCode>>=8; } else /* do nothing */ ; } CreateProgramList(); CreateObjectCode(); for (loop = 0; loop<ArrayIndex; loop++) free(IMRArray[loop]); printf("Compeleted Assembly/n"); fclose(fptr); }

 

　　sic.asm

COPY START 1000 FIRST STL RETADR CLOOP JSUB RDREC LDA LENGTH COMP ZERO JEQ ENDFIL JSUB WRREC J CLOOP ENDFIL LDA EOF STA BUFFER LDA THREE STA LENGTH JSUB WRREC LDL RETADR RSUB EOF BYTE C'EOF' THREE WORD 3 ZERO WORD 0 RETADR RESW 1 LENGTH RESW 1 BUFFER RESB 4096 . .SUBROUTINE TO READ RECORD INTO BUFFER . RDREC LDX ZERO LDA ZERO RLOOP TD INPUT JEQ RLOOP RD INPUT COMP ZERO JEQ EXIT STCH BUFFER,X TIX MAXLEN JLT RLOOP EXIT STX LENGTH RSUB INPUT BYTE X'F1' MAXLEN WORD 4096 . .SUBROUTINE TO WRITE RECORD FROM BUFFER . WRREC LDX ZERO WLOOP TD OUTPUT JEQ WLOOP LDCH BUFFER,X WD OUTPUT TIX LENGTH JLT WLOOP RSUB OUTPUT BYTE X'O5' END FIRST

 

　　Assembler这个ASM文件后的结果如下：

H^COPY  ^001000^00107a
T^001000^1e^141033^482039^001036^281030^301015^482061^3c1003^00102a^0c1039^00102d
T^00101e^15^0c1036^482061^081033^4c0000^454f46^000003^000000
T^002039^1e^041030^001030^e0205d^30203f^d8205d^281030^302057^549039^2c205e^38203f
T^002057^1c^101036^4c0000^f1^001000^041030^e02079^302064^509039^dc2079^2c1036
T^002073^07^382064^4c0000^05
E^001000

 

　　加油学习。