#include "assembly.h" #include #include #include // Max instruction width is 25 characters without the null char // // INSTRUCTIONS: // BYTE 3 BYTE 2 BYTE 1 BYTE 0 // +===================================================+ // | | | | | // +===================================================+ // // // Exception: // The bytecode 0xFFFFFFFx is an invalid command // where x is any nibble // // // INSTRUCTION FORMAT 0: // +===================================================+ // | OPCODE | 24 BIT IMMEDIATE ADDRESS | // +===================================================+ // // INSTRUCTION FORMAT 1: // +===================================================+ // | OPCODE | SOURCE REG | DEST REG | // +===================================================+ // // INSTRUCTION FORMAT 2: // +===================================================+ // | OPCODE | DEST REG | 16 BIT IMMEDIATE | // +===================================================+ // // // // OPCODE FORMAT: // ______________________________________________________________________________________________________ // |BIT | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | // +----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ // | | INSTR. FORMAT | 8bit opcode num : 16bit opcode num | // +----+-----------------+-----------------------------+-----------------------------------------------+ // // // INSTRUCTION FORMAT 0 OPCODE NUM: // +-------+----------------------------------+--------------+ // | NUM | DESCRIPTION | AFFECT FLAGS | // +-------+----------------------------------+--------------+ // | 5'd0 | NOP | NO | // +-------+----------------------------------+--------------+ // | 5'd1 | Unconditional Jump | NO | // +-------+----------------------------------+--------------+ // | 5'd2 | Jump if zero flag is set | NO | // +-------+----------------------------------+--------------+ // | 5'd3 | Jump if zero flag is not set | NO | // +-------+----------------------------------+--------------+ // | 5'd4 | Jump if carry flag is set | NO | // +-------+----------------------------------+--------------+ // | 5'd5 | Jump if carry flag is not set | NO | // // // INSTRUCTION FORMAT 1 OPCODE NUM: // +-------+----------------------------------+--------------+ // | NUM | DESCRIPTION | AFFECT FLAGS | // +-------+----------------------------------+--------------+ // | 13'd0 | ADD | YES | // +-------+----------------------------------+--------------| // | 13'd1 | SUBTRACT | YES | // +-------+----------------------------------+--------------| // | 13'd2 | SHIFT LEFT | YES | // +-------+----------------------------------+--------------| // | 13'd3 | SHIFT RIGHT | YES | // +-------+----------------------------------+--------------| // | 13'd4 | COMPARE (SUBTRACT WITHOUT SAVE) | YES | // // // INSTRUCTION FORMAT 2 OPCODE NUM: // +-------+----------------------------------------------+--------------+ // | NUM | DESCRIPTION | AFFECT FLAGS | // +-------+----------------------------------------------+--------------+ // | 5'd0 | MOV IMMEDIATE TO DEST LOW PART OF REGISTER | NO | // +-------+----------------------------------------------+--------------+ // | 5'd1 | MOV IMMEDIATE TO DEST HIGH PART OF REGISTER | NO | #define MAX_INSTRUCTION_LENGTH 26 char *disassemble(uint32_t opcode_be){ uint32_t opcode=(opcode_be&0x000000FF)<<24|(opcode_be&0x0000FF00)<<8|(opcode_be&0x00FF0000)>>8|(opcode_be&0xFF000000)>>24; char *ret=malloc(MAX_INSTRUCTION_LENGTH); if (!ret) return NULL; //////// PARSE BITECODE ////////// int instruction_format,opcode_num; uint32_t val; uint8_t val1; uint8_t val2; instruction_format=(opcode&0xE0000000)>>29; if(instruction_format==0){ // 8bit opcode opcode_num=(opcode&0x1F000000)>>24; val=opcode&0x00FFFFFF; switch(opcode_num){ case 0x00: snprintf(ret,MAX_INSTRUCTION_LENGTH,"NOP"); break; case 0x01: snprintf(ret,MAX_INSTRUCTION_LENGTH,"JMP $%06X",val); break; case 0x02: case 0x03: snprintf(ret,MAX_INSTRUCTION_LENGTH,"JMP,%s $%06X",opcode_num&1?"NZ":"Z",val); break; case 0x04: case 0x05: snprintf(ret,MAX_INSTRUCTION_LENGTH,"JMP,%s $%06X",opcode_num&1?"NC":"C",val); break; default: snprintf(ret,MAX_INSTRUCTION_LENGTH,"UNRECOGNISED INSTR"); break; } }else if(instruction_format==1){ // 16bit opcode opcode_num=(opcode&0x1FFF0000)>>16; val1=(opcode&0x0000FF00)>>8; val2=opcode&0x000000FF; switch(opcode_num){ case 0x00: snprintf(ret,MAX_INSTRUCTION_LENGTH,"ADD %%R%0d, %%R%0d",val1,val2); break; case 0x01: snprintf(ret,MAX_INSTRUCTION_LENGTH,"SUB %%R%0d, %%R%0d",val1,val2); break; case 0x02: snprintf(ret,MAX_INSTRUCTION_LENGTH,"SL %%R%0d",val1); break; case 0x03: snprintf(ret,MAX_INSTRUCTION_LENGTH,"SR %%R%0d",val1); break; case 0x04: snprintf(ret,MAX_INSTRUCTION_LENGTH,"CMP %%R%0d, %%R%0d",val1,val2); break; default: snprintf(ret,MAX_INSTRUCTION_LENGTH,"UNRECOGNISED INSTRUCTION"); break; } }else if(instruction_format==2){ // 16bit opcode opcode_num=(opcode&0x1F000000)>>24; val1=(opcode&0x00FF0000)>>16; val=opcode&0x0000FFFF; switch(opcode_num){ case 0x00: snprintf(ret,MAX_INSTRUCTION_LENGTH,"MOV $%04X, %%R%0dl",val,val1); break; case 0x01: snprintf(ret,MAX_INSTRUCTION_LENGTH,"MOV $%04X, %%R%0dh",val,val1); break; default: snprintf(ret,MAX_INSTRUCTION_LENGTH,"UNRECOGNISED INSTRUCTION"); break; } }else snprintf(ret,MAX_INSTRUCTION_LENGTH,"UNRECOGNISED INSTRUCTION"); return ret; } uint32_t assemble_line(char *line, __attribute__((unused)) struct assembler_context_t *assembler_context){ uint16_t opcode; int x; if(strncmp(line,"JMP",3)==0){ x=3; if(line[x]==' '){ opcode=0x01; }else if(line[x]==','){ x++; if(line[x]=='Z'){ opcode=0x02; x++; }else if(line[x]=='C'){ opcode=0x04; x++; }else if(line[x]=='N'){ x++; if(line[x]=='Z'){ opcode=0x03; x++; }else if(line[x]=='C'){ opcode=0x05; x++; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; while(line[x]==' ')x++; uint32_t addr; if(line[x]=='$'){ x++; if(sscanf(line+x,"%06X",&addr)!=1) return 0xFFFFFFFF; else return opcode<<24|(addr&0x00FFFFFF); }else return 0xFFFFFFFF; }else{ uint8_t r1,r0,params; if(strncmp(line,"ADD",3)==0){ x=3; opcode=0x2000; params=2; }else if(strncmp(line,"SUB",3)==0){ x=3; opcode=0x2001; params=2; }else if(strncmp(line,"SL",2)==0){ x=2; opcode=0x2002; params=1; }else if(strncmp(line,"SR",2)==0){ x=2; opcode=0x2003; params=1; }else if(strncmp(line,"CMP",3)==0){ x=3; opcode=0x2004; params=2; }else params=0; if(params!=0){ while(line[x]==' ')x++; if(line[x]=='%'){ x++; if(line[x]=='R'){ x++; if(line[x]>='0'&&line[x]<='7'){ r0=line[x]-'0'; if(params==2){ x++; while(line[x]==' ')x++; if(line[x]==','){ x++; while(line[x]==' ')x++; if(line[x]=='%'){ x++; if(line[x]=='R'){ x++; if(line[x]>='0'&&line[x]<='7'){ r1=line[x]-'0'; return (opcode<<16)|r0<<8|r1; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else return (opcode<<16)|r0<<8; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else if(strncmp(line,"MOV",3)==0){ uint32_t data; x=3; while(line[x]==' ')x++; if(line[x]=='$'){ x++; if(sscanf(line+x,"%04X",&data)==1){ x+=4; while(line[x]==' ')x++; if(line[x]==','){ x++; while(line[x]==' ')x++; if(line[x]=='%'){ x++; if(line[x]=='R'){ x++; if(line[x]>='0'&&line[x]<='7'){ r1=line[x]-'0'; x++; if(line[x]=='l') return 0x40000000|r1<<16|data; else if(line[x]=='h') return 0x41000000|r1<<16|data; else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; }else return 0xFFFFFFFF; } } void free_assembler_context(struct assembler_context_t *tofree){ free(tofree); }