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src/i386-gen.c  view on Meta::CPAN

    /* align local size to word & save local variables */
    
    v = (-loc + 3) & -4; 
    saved_ind = ind;
    ind = func_sub_sp_offset - FUNC_PROLOG_SIZE;
#ifdef TCC_TARGET_PE
    if (v >= 4096) {
        oad(0xb8, v); /* mov stacksize, %eax */
        gen_static_call(TOK___chkstk); /* call __chkstk, (does the stackframe too) */
    } else
#endif
    {
        o(0xe58955);  /* push %ebp, mov %esp, %ebp */
        o(0xec81);  /* sub esp, stacksize */
        gen_le32(v);
#ifdef TCC_TARGET_PE
        o(0x90);  /* adjust to FUNC_PROLOG_SIZE */
#endif
    }
    o(0x53 * USE_EBX); /* push ebx */
    ind = saved_ind;
}

/* generate a jump to a label */
ST_FUNC int gjmp(int t)
{
    return psym(0xe9, t);
}

/* generate a jump to a fixed address */
ST_FUNC void gjmp_addr(int a)
{
    int r;
    r = a - ind - 2;
    if (r == (char)r) {
        g(0xeb);
        g(r);
    } else {
        oad(0xe9, a - ind - 5);
    }
}

ST_FUNC void gtst_addr(int inv, int a)
{
    inv ^= (vtop--)->c.i;
    a -= ind + 2;
    if (a == (char)a) {
        g(inv - 32);
        g(a);
    } else {
        g(0x0f);
        oad(inv - 16, a - 4);
    }
}

/* generate a test. set 'inv' to invert test. Stack entry is popped */
ST_FUNC int gtst(int inv, int t)
{
    int v = vtop->r & VT_VALMASK;
    if (v == VT_CMP) {
        /* fast case : can jump directly since flags are set */
        g(0x0f);
        t = psym((vtop->c.i - 16) ^ inv, t);
    } else if (v == VT_JMP || v == VT_JMPI) {
        /* && or || optimization */
        if ((v & 1) == inv) {
            /* insert vtop->c jump list in t */
            uint32_t n1, n = vtop->c.i;
            if (n) {
                while ((n1 = read32le(cur_text_section->data + n)))
                    n = n1;
                write32le(cur_text_section->data + n, t);
                t = vtop->c.i;
            }
        } else {
            t = gjmp(t);
            gsym(vtop->c.i);
        }
    }
    vtop--;
    return t;
}

/* generate an integer binary operation */
ST_FUNC void gen_opi(int op)
{
    int r, fr, opc, c;

    switch(op) {
    case '+':
    case TOK_ADDC1: /* add with carry generation */
        opc = 0;
    gen_op8:
        if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
            /* constant case */
            vswap();
            r = gv(RC_INT);
            vswap();
            c = vtop->c.i;
            if (c == (char)c) {
                /* generate inc and dec for smaller code */
                if (c==1 && opc==0 && op != TOK_ADDC1) {
                    o (0x40 | r); // inc
                } else if (c==1 && opc==5 && op != TOK_SUBC1) {
                    o (0x48 | r); // dec
                } else {
                    o(0x83);
                    o(0xc0 | (opc << 3) | r);
                    g(c);
                }
            } else {
                o(0x81);
                oad(0xc0 | (opc << 3) | r, c);
            }
        } else {
            gv2(RC_INT, RC_INT);
            r = vtop[-1].r;
            fr = vtop[0].r;
            o((opc << 3) | 0x01);
            o(0xc0 + r + fr * 8); 
        }