Hi,
I am assuming that the reason the compiler could not safely remove these
temporary variables is because the "data" parameter in write_virtual()
is passed by pointer. Since the compiler could not prove that the value
pointed to by "data" would not be manipulated in the write_virtual()
functions, it could not make this substitution that you have made by hand.
As an alternative, one could also change the parameter in
write_virtual_word() to "const Bit16u* const data", for example. This
would allow the compiler to remove the temporaries as well since it
knows the const'ness of the parameter being passed. Also, the current
changes that you propose are not safe against a bug in write_virtual()
that may try to manipulate (*data).
Just a thought.
Brian
Conn Clark wrote:
Hello All,
Now that our company has gotten our mail server hosting company
straightened out on our mail server settings I can finaly join the
bochs developers list.
To celebrate I have rewritten a patch that I submitted before that
boost performance a bit. Hopefully this will not cause troubles for
the X86-64 users like my last one did.
Unlike my previous speedups this one will help more platforms than
just X86. It cleans up the Data Xfer instructions. Since the Data Xfer
instructions are the most often executed instructions it gives a
noticable boost in speed (Not a lot but some). The basic optimization
technique was to eliminate intermediate variables and pass a pointer
to the final destination or original source to the
read_virtual_whatever and the write_virtual_whatever functions. This
patch was taken from a CVS download on Nov. 21 2003 .
I have tested this patch on a PC running Linux and on A Mac
running OSX 10.3 . I have booted the Dlxlinux image on the Mac and
booted WinDOS 98 on the PC. I have not done any X86-64 testing and I
need someone who knows about it to do it.
PS.
For anybody doing X86-64 testing on this patch, I would like to
have you test out my pipelined-asm patch that is already in the
patches dirrectory in CVS.
Many Thanks in advance,
Conn Clark ( Aka psychosmurf & Obscene_CNN )
------------------------------------------------------------------------
Only in bochs: .bochsrc
Only in bochs: .conf.AIX.4.3.1
Only in bochs: .conf.amigaos
Only in bochs: .conf.beos
Only in bochs: .conf.everything
Only in bochs: .conf.linux
Only in bochs: .conf.macos
Only in bochs: .conf.macosx
Only in bochs: .conf.sparc
Only in bochs: .conf.win32
Only in bochs: .conf.win32-cygwin
Only in bochs: .conf.win32-vcpp
Only in bochs: .cvsignore
diff -ru bochs/cpu/data_xfer16.cc bochs-modified/cpu/data_xfer16.cc
--- bochs/cpu/data_xfer16.cc Thu Nov 13 13:57:12 2003
+++ bochs-modified/cpu/data_xfer16.cc Fri Nov 21 14:02:59 2003
@@ -54,11 +54,7 @@
void
BX_CPU_C::MOV_EEwGw(bxInstruction_c *i)
{
- Bit16u op2_16;
-
- op2_16 = BX_READ_16BIT_REG(i->nnn());
-
- write_virtual_word(i->seg(), RMAddr(i), &op2_16);
+ write_virtual_word(i->seg(), RMAddr(i), &BX_READ_16BIT_REG(i->nnn()));
}
void
@@ -86,10 +82,8 @@
BX_CPU_C::MOV_GwEEw(bxInstruction_c *i)
{
// 2nd modRM operand Ex, is known to be a memory operand, Ew.
- Bit16u op2_16;
- read_virtual_word(i->seg(), RMAddr(i), &op2_16);
- BX_WRITE_16BIT_REG(i->nnn(), op2_16);
+ read_virtual_word(i->seg(), RMAddr(i), &BX_READ_16BIT_REG(i->nnn()));
}
void
@@ -165,7 +159,6 @@
void
BX_CPU_C::MOV_AXOw(bxInstruction_c *i)
{
- Bit16u temp_16;
bx_address addr;
addr = i->Id();
@@ -173,34 +166,27 @@
/* read from memory address */
if (!BX_NULL_SEG_REG(i->seg())) {
- read_virtual_word(i->seg(), addr, &temp_16);
+ read_virtual_word(i->seg(), addr, &AX);
}
else {
- read_virtual_word(BX_SEG_REG_DS, addr, &temp_16);
+ read_virtual_word(BX_SEG_REG_DS, addr, &AX);
}
-
- /* write to register */
- AX = temp_16;
}
void
BX_CPU_C::MOV_OwAX(bxInstruction_c *i)
{
- Bit16u temp_16;
bx_address addr;
addr = i->Id();
- /* read from register */
- temp_16 = AX;
-
/* write to memory address */
if (!BX_NULL_SEG_REG(i->seg())) {
- write_virtual_word(i->seg(), addr, &temp_16);
+ write_virtual_word(i->seg(), addr, &AX);
}
else {
- write_virtual_word(BX_SEG_REG_DS, addr, &temp_16);
+ write_virtual_word(BX_SEG_REG_DS, addr, &AX);
}
}
diff -ru bochs/cpu/data_xfer32.cc bochs-modified/cpu/data_xfer32.cc
--- bochs/cpu/data_xfer32.cc Sat Oct 4 13:48:13 2003
+++ bochs-modified/cpu/data_xfer32.cc Fri Nov 21 14:31:20 2003
@@ -63,11 +63,7 @@
void
BX_CPU_C::MOV_EEdGd(bxInstruction_c *i)
{
- Bit32u op2_32;
-
- op2_32 = BX_READ_32BIT_REG(i->nnn());
-
- write_virtual_dword(i->seg(), RMAddr(i), &op2_32);
+ write_virtual_dword(i->seg(), RMAddr(i), &BX_READ_32BIT_REG(i->nnn()));
}
void
@@ -95,10 +91,14 @@
BX_CPU_C::MOV_GdEEd(bxInstruction_c *i)
{
// 2nd modRM operand Ex, is known to be a memory operand, Ed.
- Bit32u op2_32;
+// Bit32u op2_32;
- read_virtual_dword(i->seg(), RMAddr(i), &op2_32);
- BX_WRITE_32BIT_REGZ(i->nnn(), op2_32);
+// read_virtual_dword(i->seg(), RMAddr(i), &op2_32);
+// BX_WRITE_32BIT_REGZ(i->nnn(), op2_32);
+#if BX_SUPPORT_X86_64
+ BX_CPU_THIS_PTR gen_reg[i->nnn()].hrx = 0;
+#endif
+ read_virtual_dword(i->seg(), RMAddr(i), &BX_READ_32BIT_REG(i->nnn()));
}
void
@@ -118,46 +118,40 @@
void
BX_CPU_C::MOV_EAXOd(bxInstruction_c *i)
{
- Bit32u temp_32;
bx_address addr;
+#if BX_SUPPORT_X86_64
+ BX_CPU_THIS_PTR gen_reg[0].hrx = 0;
+#endif
+
addr = i->Id();
/* read from memory address */
if (!BX_NULL_SEG_REG(i->seg())) {
- read_virtual_dword(i->seg(), addr, &temp_32);
+ read_virtual_dword(i->seg(), addr, &EAX);
}
else {
- read_virtual_dword(BX_SEG_REG_DS, addr, &temp_32);
+ read_virtual_dword(BX_SEG_REG_DS, addr, &EAX);
}
- /* write to register */
-#if BX_SUPPORT_X86_64
- RAX = temp_32;
-#else
- EAX = temp_32;
-#endif
+
}
void
BX_CPU_C::MOV_OdEAX(bxInstruction_c *i)
{
- Bit32u temp_32;
bx_address addr;
addr = i->Id();
- /* read from register */
- temp_32 = EAX;
-
/* write to memory address */
if (!BX_NULL_SEG_REG(i->seg())) {
- write_virtual_dword(i->seg(), addr, &temp_32);
+ write_virtual_dword(i->seg(), addr, &EAX);
}
else {
- write_virtual_dword(BX_SEG_REG_DS, addr, &temp_32);
+ write_virtual_dword(BX_SEG_REG_DS, addr, &EAX);
}
}
diff -ru bochs/cpu/data_xfer8.cc bochs-modified/cpu/data_xfer8.cc
--- bochs/cpu/data_xfer8.cc Thu May 8 10:56:48 2003
+++ bochs-modified/cpu/data_xfer8.cc Fri Nov 21 13:55:18 2003
@@ -50,11 +50,7 @@
void
BX_CPU_C::MOV_EEbGb(bxInstruction_c *i)
{
- Bit8u op2;
-
- op2 = BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL());
-
- write_virtual_byte(i->seg(), RMAddr(i), &op2);
+ write_virtual_byte(i->seg(), RMAddr(i),
&BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL()));
}
void
@@ -71,11 +67,9 @@
void
BX_CPU_C::MOV_GbEEb(bxInstruction_c *i)
{
- Bit8u op2;
- read_virtual_byte(i->seg(), RMAddr(i), &op2);
+ read_virtual_byte(i->seg(), RMAddr(i),
&BX_READ_8BIT_REGx(i->nnn(),i->extend8bitL()));
- BX_WRITE_8BIT_REGx(i->nnn(), i->extend8bitL(), op2);
}
void
@@ -93,22 +87,20 @@
void
BX_CPU_C::MOV_ALOb(bxInstruction_c *i)
{
- Bit8u temp_8;
bx_address addr;
addr = i->Id();
/* read from memory address */
if (!BX_NULL_SEG_REG(i->seg())) {
- read_virtual_byte(i->seg(), addr, &temp_8);
+ read_virtual_byte(i->seg(), addr, &AL);
}
else {
- read_virtual_byte(BX_SEG_REG_DS, addr, &temp_8);
+ read_virtual_byte(BX_SEG_REG_DS, addr, &AL);
}
/* write to register */
- AL = temp_8;
}
@@ -120,15 +112,13 @@
addr = i->Id();
- /* read from register */
- temp_8 = AL;
/* write to memory address */
if (!BX_NULL_SEG_REG(i->seg())) {
- write_virtual_byte(i->seg(), addr, &temp_8);
+ write_virtual_byte(i->seg(), addr, &AL);
}
else {
- write_virtual_byte(BX_SEG_REG_DS, addr, &temp_8);
+ write_virtual_byte(BX_SEG_REG_DS, addr, &AL);
}
}
@@ -155,8 +145,6 @@
BX_CPU_C::XLAT(bxInstruction_c *i)
{
Bit32u offset_32;
- Bit8u al;
-
#if BX_CPU_LEVEL >= 3
if (i->as32L()) {
@@ -169,12 +157,11 @@
}
if (!BX_NULL_SEG_REG(i->seg())) {
- read_virtual_byte(i->seg(), offset_32, &al);
+ read_virtual_byte(i->seg(), offset_32, &AL);
}
else {
- read_virtual_byte(BX_SEG_REG_DS, offset_32, &al);
+ read_virtual_byte(BX_SEG_REG_DS, offset_32, &AL);
}
- AL = al;
}
void
-------------------------------------------------------
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