static BOOL check_reg_type(const struct shader_reg *reg,
                           const struct allowed_reg_type *allowed) {
    unsigned int i = 0;

    while(allowed[i].type != ~0U) {
        if(reg->type == allowed[i].type) {
            if(reg->rel_reg) return TRUE; /* The relative addressing register
                                             can have a negative value, we
                                             can't check the register index */
            if(reg->regnum < allowed[i].count) return TRUE;
            else return FALSE;
        }
        i++;
    }
    return FALSE;
}

/* Native compiler doesn't make separate checks for src and dst registers */
struct allowed_reg_type vs_1_reg_allowed[] = {
    { BWRITERSPR_TEMP,     12 },
    { BWRITERSPR_INPUT,    16 },
    { BWRITERSPR_CONST,   ~0U },
    { BWRITERSPR_ADDR,      1 },
    { BWRITERSPR_RASTOUT,   3 }, /* oPos, oFog and oPts */
    { BWRITERSPR_ATTROUT,   2 },
    { BWRITERSPR_TEXCRDOUT, 8 },
    { ~0U, 0 } /* End tag */
};

static void asmparser_srcreg_vs_1(struct asm_parser *This,
                                  struct instruction *instr, int num,
                                  const struct shader_reg *src) {
    struct shader_reg reg;

    if(!check_reg_type(src, vs_1_reg_allowed)) {
        asmparser_message(This, "Line %u: Source register %s not supported in VS 1\n",
                          This->line_no,
                          debug_print_srcreg(src, ST_VERTEX));
        set_parse_status(This, PARSE_ERR);
    }
    check_legacy_srcmod(This, src->srcmod);
    check_abs_srcmod(This, src->srcmod);
    reg = map_oldvs_register(src);
    memcpy(&instr->src[num], &reg, sizeof(reg));
}