#include "desfx.h"
#include "6502emu.h"
#include "log.h"

static void mem_access_write(struct mem_access *this, u16 address, u8 value)
{
    u8 *mem = this->ctx;
    mem[address] = value;
}

static u8 mem_access_read(struct mem_access *this, u16 address)
{
    u8 *mem = this->ctx;
    return mem[address];
}

u16 decrunch_sfx(u8 mem[65536], u16 run, u16 *startp, u16 *endp)
{
    struct cpu_ctx r;
    u16 start;
    u16 end;
    r.cycles = 0;
    r.mem.ctx = mem;
    r.mem.read = mem_access_read;
    r.mem.write = mem_access_write;
    r.pc = run;
    r.sp = '\xf6';
    r.flags = 0;

    LOG(LOG_DEBUG, ("run %04x\n", run));

    /* setting up decrunch */
    while(r.pc >= 0x0400 || r.sp != 0xf6)
    {
        next_inst(&r);
    }
    end = mem_access_read_u16le(&r.mem, 0xfe);

    LOG(LOG_DEBUG, ("end %04x @%u\n", end, r.cycles));
    hex_dump(LOG_DEBUG, mem + 0x334, 156);

    /* decrunching */
    while(r.pc < 0x400)
    {
        /* is this an absolute sta, stx or sty to the IO-area? */
        int op_code = MEM_ACCESS_READ(&r.mem, r.pc);
        int addr = mem_access_read_u16le(&r.mem, r.pc + 1);

        if((op_code == 0x8d || op_code == 0x8e || op_code == 0x8c) &&
           addr >= 0xd000 && addr < 0xe000)
        {
            /* ignore it, its probably an effect */
            LOG(LOG_DEBUG, ("ignoring sta/stx/sty to IO %02x $%04X\n",
                           op_code, addr));
            r.pc += 3;
        }

        next_inst(&r);
    }
    start = mem_access_read_u16le(&r.mem, 0xfe);
    LOG(LOG_DEBUG, ("start %04x @%u\n", start, r.cycles));

    if(startp != NULL)
    {
        *startp = start;
    }
    if(endp != NULL)
    {
        *endp = end;
    }
    return r.pc;
}