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b79375a0c5
ia32: no longer needs #if since build system ensures it's not compiled on amd64 This was SVN commit r6164.
114 lines
3.8 KiB
C++
114 lines
3.8 KiB
C++
/**
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* =========================================================================
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* File : ia32.cpp
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* Project : 0 A.D.
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* Description : routines specific to IA-32
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* =========================================================================
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*/
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// license: GPL; see lib/license.txt
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#include "precompiled.h"
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#include "ia32.h"
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#include "lib/sysdep/cpu.h"
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#include "ia32_memcpy.h"
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#include "ia32_asm.h"
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LibError ia32_GetCallTarget(void* ret_addr, void** target)
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{
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*target = 0;
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// points to end of the CALL instruction (which is of unknown length)
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const u8* c = (const u8*)ret_addr;
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// this would allow for avoiding exceptions when accessing ret_addr
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// close to the beginning of the code segment. it's not currently set
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// because this is really unlikely and not worth the trouble.
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const size_t len = ~0u;
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// CALL rel32 (E8 cd)
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if(len >= 5 && c[-5] == 0xE8)
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{
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*target = (u8*)ret_addr + *(i32*)(c-4);
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return INFO::OK;
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}
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// CALL r/m32 (FF /2)
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// .. CALL [r32 + r32*s] => FF 14 SIB
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if(len >= 3 && c[-3] == 0xFF && c[-2] == 0x14)
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return INFO::OK;
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// .. CALL [disp32] => FF 15 disp32
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if(len >= 6 && c[-6] == 0xFF && c[-5] == 0x15)
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{
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void* addr_of_target = *(void**)(c-4);
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// there are no meaningful checks we can perform: we're called from
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// the stack trace code, so ring0 addresses may be legit.
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// even if the pointer is 0, it's better to pass its value on
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// (may help in tracking down memory corruption)
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*target = *(void**)addr_of_target;
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return INFO::OK;
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}
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// .. CALL [r32] => FF 00-3F(!14/15)
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if(len >= 2 && c[-2] == 0xFF && c[-1] < 0x40 && c[-1] != 0x14 && c[-1] != 0x15)
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return INFO::OK;
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// .. CALL [r32 + r32*s + disp8] => FF 54 SIB disp8
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if(len >= 4 && c[-4] == 0xFF && c[-3] == 0x54)
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return INFO::OK;
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// .. CALL [r32 + disp8] => FF 50-57(!54) disp8
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if(len >= 3 && c[-3] == 0xFF && (c[-2] & 0xF8) == 0x50 && c[-2] != 0x54)
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return INFO::OK;
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// .. CALL [r32 + r32*s + disp32] => FF 94 SIB disp32
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if(len >= 7 && c[-7] == 0xFF && c[-6] == 0x94)
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return INFO::OK;
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// .. CALL [r32 + disp32] => FF 90-97(!94) disp32
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if(len >= 6 && c[-6] == 0xFF && (c[-5] & 0xF8) == 0x90 && c[-5] != 0x94)
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return INFO::OK;
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// .. CALL r32 => FF D0-D7
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if(len >= 2 && c[-2] == 0xFF && (c[-1] & 0xF8) == 0xD0)
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return INFO::OK;
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WARN_RETURN(ERR::CPU_UNKNOWN_OPCODE);
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}
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void cpu_ConfigureFloatingPoint()
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{
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// no longer set 24 bit (float) precision by default: for
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// very long game uptimes (> 1 day; e.g. dedicated server),
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// we need full precision when calculating the time.
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// if there's a spot where we want to speed up divides|sqrts,
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// we can temporarily change precision there.
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//ia32_asm_control87(IA32_PC_24, IA32_MCW_PC);
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// to help catch bugs, enable as many floating-point exceptions as
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// possible. unfortunately SpiderMonkey triggers all of them.
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// note: passing a flag *disables* that exception.
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ia32_asm_control87(IA32_EM_ZERODIVIDE|IA32_EM_INVALID|IA32_EM_DENORMAL|IA32_EM_OVERFLOW|IA32_EM_UNDERFLOW|IA32_EM_INEXACT, IA32_MCW_EM);
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// no longer round toward zero (truncate). changing this setting
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// resulted in much faster float->int casts, because the compiler
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// could be told (via /QIfist) to use FISTP while still truncating
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// the result as required by ANSI C. however, FPU calculation
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// results were changed significantly, so it had to be disabled.
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//ia32_asm_control87(IA32_RC_CHOP, IA32_MCW_RC);
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}
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void cpu_AtomicAdd(volatile intptr_t* location, intptr_t increment)
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{
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ia32_asm_AtomicAdd(location, increment);
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}
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bool cpu_CAS(volatile uintptr_t* location, uintptr_t expected, uintptr_t new_value)
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{
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return ia32_asm_CAS(location, expected, new_value);
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}
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void* cpu_memcpy(void* RESTRICT dst, const void* RESTRICT src, size_t size)
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{
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return ia32_memcpy(dst, src, size);
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}
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