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/* ========================================================================
(C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Please see https://computerenhance.com for more information
======================================================================== */
#include <stdio.h>
#include <string.h>
#include "sim86.h"
#include "sim86_shared.h"
internal void
Run8086(psize DisassemblySize, u8 *Disassembly)
{
s32 Registers[Register_count] = {};
u32 Offset = 0;
while(Offset < DisassemblySize)
{
instruction Decoded;
Sim86_Decode8086Instruction(DisassemblySize - Offset, Disassembly + Offset, &Decoded);
if(Decoded.Op)
{
Offset += Decoded.Size;
#if SIM86_INTERNAL
printf("Size:%u Op:%s Flags:0x%x\n", Decoded.Size, Sim86_MnemonicFromOperationType(Decoded.Op), Decoded.Flags);
#endif
if(0) {}
else if(Decoded.Op == Op_mov)
{
s32 *Destination = 0;
s32 *Source = 0;
if(0) {}
else if(Decoded.Operands[0].Type == Operand_Register)
{
Destination = &Registers[Decoded.Operands[0].Register.Index];
}
else if(Decoded.Operands[0].Type == Operand_Memory)
{
Assert(0 && "mov to memory not implemented yet.");
}
else if(Decoded.Operands[0].Type == Operand_Immediate)
{
Assert(0 && "Cannot move to immediate value.");
}
else
{
Assert(0);
}
if(0) {}
else if(Decoded.Operands[1].Type == Operand_Register)
{
Source = &Registers[Decoded.Operands[1].Register.Index];
}
else if(Decoded.Operands[1].Type == Operand_Immediate)
{
Source = &Decoded.Operands[1].Immediate.Value;
}
else if(Decoded.Operands[1].Type == Operand_Memory)
{
Assert(0 && "mov from memory not implemented yet.");
}
else
{
Assert(0);
}
*Destination = *Source;
}
else
{
Assert(0 && "Op not implemented yet.");
}
}
else
{
printf("Unrecognized instruction\n");
break;
}
}
printf("Final registers:\n");
for(u32 RegisterIndex = Register_a;
RegisterIndex < Register_di + 1;
RegisterIndex++)
{
register_access Register = {};
Register.Index = RegisterIndex;
Register.Offset = 0;
Register.Count = 2;
printf(" %s: 0x%04x (%d)\n",
Sim86_RegisterNameFromOperand(&Register),
Registers[RegisterIndex],
Registers[RegisterIndex]);
}
}
void PrintUsage(char *ExePath)
{
fprintf(stderr, "usage: %s [-exec] <assembly>\n", ExePath);
}
int main(int ArgCount, char *Args[])
{
u32 Version = Sim86_GetVersion();
#if SIM86_INTERNAL
printf("Sim86 Version: %u (expected %u)\n", Version, SIM86_VERSION);
#endif
if(Version != SIM86_VERSION)
{
printf("ERROR: Header file version doesn't match DLL.\n");
return -1;
}
instruction_table Table;
Sim86_Get8086InstructionTable(&Table);
#if SIM86_INTERNAL
printf("8086 Instruction Instruction Encoding Count: %u\n", Table.EncodingCount);
#endif
// print (default)
// -exec (also execute the disassembled instructinos)
b32 Execute = false;
char *FileName = 0;
if(ArgCount == 2)
{
FileName = Args[1];
Execute = false;
// Print disassembly from assembly
}
else if(ArgCount == 3)
{
char *Command = Args[1];
FileName = Args[2];
if(!strcmp(Command, "-exec"))
{
Execute = true;
}
else
{
fprintf(stderr, "ERROR: Unknown command %s.\n", Command);
PrintUsage(Args[0]);
}
}
else
{
PrintUsage(Args[0]);
}
u8 Memory[1024] = {};
if(FileName)
{
FILE *File = fopen(FileName, "rb");
if(File)
{
psize Result = fread(Memory, 1, sizeof(Memory), File);
fclose(File);
if(Execute)
{
printf("--- %s execution ---\n", FileName);
Run8086(Result, Memory);
}
else
{
fprintf(stderr, "ERROR: Disassembling not implemented yet.\n");
}
}
else
{
fprintf(stderr, "ERROR: Unable to open %s.\n", FileName);
PrintUsage(Args[0]);
}
}
return 0;
}
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