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/* Licensed under the zlib/libpng license (same as NSIS) */
/*
CPUID hepler module for the Nullsoft Installer (NSIS).
The exported cpuid_available and cpuid functions should be used
with the cpuid.nsh header.
*/
.text
/*
Check if CPUID opcode is available by toggling ID bit in EFLAGS register
Returns a non-zero value if CPUID opcode is available otherwise 0.
C function declaration:
__declspec(dllexport) unsigned int __attribute__((__stdcall__))
cpuid_available(void)
*/
.globl _cpuid_available@0
_cpuid_available@0:
/* Transfer content of EFLAGS register into ECX via stack */
pushfl
popl %ecx
/* Save original content of EFLAGS register in EAX */
movl %ecx, %eax
/* Toggle ID bit (bit number: 21) */
xorl $0x00200000, %ecx
/* Update EFLAGS register with the contents of ECX and
read back EFLAGS into ECX */
pushl %ecx
popfl
pushfl
popl %ecx
/* Restore original content of EFLAGS register */
pushl %eax
popfl
/* If ID bit could be modified in EFLAGS register then the
exclusive-or (XOR) operation leads to a non-zero value in EAX */
xorl %ecx, %eax
ret
/*
Invoke CPUID opcode
Parameters:
info - array of four 32 bit intergers getting the contents of the registers EAX, EBX, ECX and EDX
id - query code
C function declaration:
__declspec(dllexport) void __attribute__((__stdcall__))
cpuid(unsigned int info[4], unsigned int id)
*/
.globl _cpuid@8
_cpuid@8:
pushl %ebp
movl %esp, %ebp
pushl %esi
pushl %ebx
movl 8(%ebp), %esi
/* Write query code to EAX */
movl 12(%ebp), %eax
cpuid
/* Save contents of the registers EAX, EBX, ECX and EDX
in the provided array */
movl %eax, (%esi)
movl %ebx, 4(%esi)
movl %ecx, 8(%esi)
movl %edx, 12(%esi)
popl %ebx
popl %esi
popl %ebp
ret $8
/*
C function declaration:
BOOL __attribute__((__stdcall__))
DllEntryPoint(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
*/
.globl _DllEntryPoint@12
_DllEntryPoint@12:
movl $1, %eax
ret $12
.section .drectve
.ascii " -export:\"cpuid@8\""
.ascii " -export:\"cpuid_available@0\""
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