Method ret

source/emulation/cpu/common/cpu.cpp:551–662

}

void CPU::ret(U32 big, U32 bytes) {
    if (this->flags & VM) {
        U32 new_ip = 0;
        U32 new_cs = 0;
        if (big) {
            new_ip = pop32();
            new_cs = pop32() & 0xffff;            
        } else {
            new_ip = pop16();
            new_cs = pop16();
        }
        THIS_ESP = (THIS_ESP & this->stackNotMask) | ((THIS_ESP + bytes ) & this->stackMask);
        this->setSegment(CS, new_cs);
        this->eip.u32 = new_ip;
        this->setIsBig(0);
    } else {
        U32 selector = 0;

        if (big) 
            selector = peek32(1);
        else 
            selector = peek16(1);

        U32 rpl=selector & 3; // requested privilege level
        if(rpl < this->cpl) {
            this->prepareException(EXCEPTION_GP, selector & 0xfffc);
            return;
        }        
        U32 index = selector >> 3;

        if (CPU_CHECK_COND(this, (selector & 0xfffc)==0, "RET:CS selector zero", EXCEPTION_GP,0))
            return;

        if (index>=LDT_ENTRIES) {
            CPU_CHECK_COND(this, 0, "RET:CS beyond limits", EXCEPTION_GP,selector & 0xfffc);
            return;
        }
        struct user_desc* ldt = this->thread->getLDT(index);
        if (this->thread->isLdtEmpty(ldt)) {
            this->prepareException(EXCEPTION_NP, selector & 0xfffc);
            return;
        }
        if (this->cpl==rpl) {
            // Return to same level             
            U32 offset = 0;
            if (big) {
                offset = pop32();
                selector = pop32() & 0xffff;
            } else {
                offset = pop16();
                selector = pop16();
            }
            this->setSeg(CS, ldt->base_addr, selector);
            this->setIsBig(ldt->seg_32bit);
            this->eip.u32 = offset;
            THIS_ESP = (THIS_ESP & this->stackNotMask) | ((THIS_ESP + bytes ) & this->stackMask);
        } else {
            // Return to outer level