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Fully handle segment limits inside prefetch method.

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1. Should speed up the simulation (eliminate seg.limit check per every instruction exec)
2. Should help for DT (h.johansson request)
This commit is contained in:
Stanislav Shwartsman 2006-05-04 19:54:25 +00:00
parent 9340f3b3f8
commit 767fb77ebd
1 changed files with 10 additions and 16 deletions
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26
bochs/cpu/cpu.cc
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@ -1,5 +1,5 @@
/////////////////////////////////////////////////////////////////////////
// $Id: cpu.cc,v 1.149 2006-04-29 16:14:45 sshwarts Exp $
// $Id: cpu.cc,v 1.150 2006-05-04 19:54:25 sshwarts Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001 MandrakeSoft S.A.
@ -287,15 +287,7 @@ void BX_CPU_C::cpu_loop(Bit32u max_instr_count)
// fetch and decode next instruction
bxInstruction_c *i = fetchInstruction(&iStorage, eipBiased);
bx_address next_RIP = RIP + i->ilen();
if (! Is64BitMode()) {
if (((Bit32u) next_RIP - 1) > BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled) {
BX_ERROR(("GP(0): instruction cross segment boundary !"));
exception(BX_GP_EXCEPTION, 0, 0);
}
}
BxExecutePtr_tR resolveModRM = i->ResolveModrm; // Get as soon as possible for speculation
BxExecutePtr_t execute = i->execute; // fetch as soon as possible for speculation
if (resolveModRM)
@ -741,18 +733,24 @@ unsigned BX_CPU_C::handleAsyncEvent(void)
void BX_CPU_C::prefetch(void)
{
bx_phy_address pAddr;
bx_address temp_rip = RIP;
bx_address laddr = BX_CPU_THIS_PTR get_segment_base(BX_SEG_REG_CS) + temp_rip;
bx_phy_address pAddr;
// Calculate RIP at the beginning of the page.
bx_address eipPageOffset0 = RIP - (laddr & 0xfff);
BX_CPU_THIS_PTR eipPageBias = -eipPageOffset0;
BX_CPU_THIS_PTR eipPageWindowSize = 4096;
if (! Is64BitMode()) {
Bit32u temp_limit = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled;
if (((Bit32u) temp_rip) > temp_limit) {
BX_ERROR(("prefetch: EIP [%08x] > CS.limit [%08x]", (Bit32u) temp_rip, temp_limit));
exception(BX_GP_EXCEPTION, 0, 0);
}
if (temp_limit + BX_CPU_THIS_PTR eipPageBias < 4096) {
BX_CPU_THIS_PTR eipPageWindowSize = temp_limit + BX_CPU_THIS_PTR eipPageBias + 1;
}
}
#if BX_SUPPORT_PAGING
@ -767,10 +765,6 @@ void BX_CPU_C::prefetch(void)
pAddr = A20ADDR(laddr);
}
// Calculate RIP at the beginning of the page.
bx_address eipPageOffset0 = RIP - (laddr & 0xfff);
BX_CPU_THIS_PTR eipPageBias = -eipPageOffset0;
BX_CPU_THIS_PTR eipPageWindowSize = 4096;
BX_CPU_THIS_PTR pAddrA20Page = pAddr & 0xfffff000;
BX_CPU_THIS_PTR eipFetchPtr =
BX_CPU_THIS_PTR mem->getHostMemAddr(BX_CPU_THIS,