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#include "V86Thread.class.h"
#include <TaskManager/Task.ns.h>
#include <TaskManager/V86/V86.ns.h>
//in v86.wtf.asm
extern "C" void v86_run(u32int pd_phys, //A page directory's physical address
v86_regs_t* regs);
/*
* Set up a V86 task :
* Allocate space for the kernel stack
* Map frames in lower 1MB
* Find somewhere to put the stack and the code, still in lower 1MB
* Copy the 16bit code to that place
* Setup values on the kernel stack for starting the thread (V86Thread::runV86),
* giving it entry point and stack location
*/
V86Thread::V86Thread(v86_function_t* entry, v86_retval_t* ret) : Thread() {
m_ret = ret;
setup();
m_continueOnIret = true;
m_ret->regs->cs = V86::allocSeg(entry->size); //Alocate segments for the code to run in
u8int* codeptr = (u8int*)(FP_TO_LINEAR(m_ret->regs->cs, 0));
memcpy(codeptr, entry->data, entry->size); //Copy the code there
m_ret->regs->ip = 0;
m_state = T_RUNNING;
m_process->registerThread(this);
Task::registerThread(this);
}
V86Thread::V86Thread(u8int int_no, v86_retval_t* ret) : Thread() {
m_ret = ret;
setup();
m_continueOnIret = false;
//setup CS:IP for running interrupt
u16int* ivt = 0;
m_ret->regs->cs = ivt[int_no * 2 + 1];
m_ret->regs->ip = ivt[int_no * 2];
m_state = T_RUNNING;
m_process->registerThread(this);
Task::registerThread(this);
}
void V86Thread::setup() {
m_ret->finished = false; m_xchgspace = 0; m_isKernel = true;
m_process = Task::currProcess();
m_if = true; //Set virtual interrupt flag
m_kernelStack.addr = Mem::alloc(STACKSIZE); m_kernelStack.size = STACKSIZE; //Setup kernel stack
m_process->getPagedir()->switchTo();
//Map all lower memory
V86::map();
//Allocate space for v86 stack
m_ret->regs->ss = V86::allocSeg(V86_STACKSIZE);
m_ret->regs->sp = V86_STACKSIZE - 4;
//Setup kernel stack for running v86_run (entry procedure)
u32int* stack = (u32int*)((u32int)m_kernelStack.addr + m_kernelStack.size);
stack--; *stack = (u32int)m_ret->regs;
stack--; *stack = m_process->getPagedir()->physicalAddr;
stack--; *stack = 0;
m_esp = (u32int)stack;
m_ebp = m_esp + 4;
m_eip = (u32int)v86_run;
}
bool V86Thread::handleV86GPF(registers_t *regs) {
u8int* ip = (u8int*)FP_TO_LINEAR(regs->cs, regs->eip);
u16int *ivt = 0;
u16int *stack = (u16int*)FP_TO_LINEAR(regs->ss, (regs->useresp & 0xFFFF));
u32int *stack32 = (u32int*)stack;
bool is_operand32 = false, is_address32 = false;
while (true) {
switch (ip[0]) {
case 0x66: // O32
is_operand32 = true;
ip++; regs->eip = (u16int)(regs->eip + 1);
break;
case 0x67: // A32
is_address32 = true;
ip++; regs->eip = (u16int)(regs->eip + 1);
break;
case 0x9C: // PUSHF
if (is_operand32) {
regs->useresp = ((regs->useresp & 0xFFFF) - 4) & 0xFFFF;
stack32--;
*stack32 = regs->eflags & VALID_FLAGS;
if (m_if)
*stack32 |= EFLAGS_IF;
else
*stack32 &= ~EFLAGS_IF;
} else {
regs->useresp = ((regs->useresp & 0xFFFF) - 2) & 0xFFFF;
stack--;
*stack = regs->eflags;
if (m_if)
*stack |= EFLAGS_IF;
else
*stack &= ~EFLAGS_IF;
}
regs->eip = (u16int)(regs->eip + 1);
return true;
case 0x9D: // POPF
if (is_operand32) {
regs->eflags = EFLAGS_IF | EFLAGS_VM | (stack32[0] & VALID_FLAGS);
m_if = (stack32[0] & EFLAGS_IF) != 0;
regs->useresp = ((regs->useresp & 0xFFFF) + 4) & 0xFFFF;
} else {
regs->eflags = EFLAGS_IF | EFLAGS_VM | stack[0];
m_if = (stack[0] & EFLAGS_IF) != 0;
regs->useresp = ((regs->useresp & 0xFFFF) + 2) & 0xFFFF;
}
regs->eip = (u16int)(regs->eip + 1);
return true;
case 0xCD: // INT N
if (ip[1] == 3) return false; //Breakpoint exception, here used for telling that thread has ended
stack -= 3;
regs->useresp = ((regs->useresp & 0xFFFF) - 6) & 0xFFFF;
stack[0] = (u16int)(regs->eip + 2);
stack[1] = regs->cs;
stack[2] = (u16int)regs->eflags;
regs->cs = ivt[ip[1] * 2 + 1];
regs->eip = ivt[ip[1] * 2];
return true;
case 0xCF: // IRET
regs->eip = stack[0];
regs->cs = stack[1];
regs->eflags = EFLAGS_IF | EFLAGS_VM | stack[2];
m_if = (stack[2] & EFLAGS_IF) != 0;
regs->useresp = ((regs->useresp & 0xFFFF) + 6) & 0xFFFF;
return m_continueOnIret;
case 0xFA: // CLI
m_if = false;
regs->eip = (u16int)(regs->eip + 1);
return true;
case 0xFB: // STI
m_if = true;
regs->eip = (u16int)(regs->eip + 1);
return true;
default:
return false;
}
}
}
void V86Thread::handleException(registers_t *regs, int no) {
if (no == 13) { //General protection fault
if (!handleV86GPF(regs)) {
m_ret->finished = true;
m_ret->regs->ax = (u16int)regs->eax;
m_ret->regs->bx = (u16int)regs->ebx;
m_ret->regs->cx = (u16int)regs->ecx;
m_ret->regs->dx = (u16int)regs->edx;
m_ret->regs->di = (u16int)regs->edi;
m_ret->regs->si = (u16int)regs->esi;
Task::currentThreadExits(0);
return;
}
} else {
Thread::handleException(regs, no);
}
}
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