intstub.cpp

伯克利做的SFTP安全文件传输协议

// intstub.cc
// purpose is to generate intstub.asm
// copyright SafeTP Development Group, Inc., 2000  Terms of use are as specified in license.txt

// integer.cpp - written and placed in the public domain by Wei Dai

//#include "pch.h"
#include "integer.h"
#include "modarith.h"
#include "nbtheory.h"
#include "asn.h"
#include "words.h"

#ifdef SAFETP
# include "iostream.h"
# include <string.h>       // strlen
#else
# include "iostream"
  USING_NAMESPACE(std)
#endif // !SAFETP

#include "algebra.cc"
#include "eprecomp.cc"

#define MAKE_DWORD(lowWord, highWord) ((dword(highWord)<<WORD_BITS) | (lowWord))

#if defined(_MSC_VER) && defined(_M_IX86) && (_M_IX86<=500)

// Add() and Subtract() are coded in Pentium assembly for a speed increase
// of about 10-20 percent for a RSA signature

static /*__declspec(naked)*/ word __fastcall Add(word *C, const word *A, const word *B, unsigned int N)
{
	__asm
	{
		push ebp
		push ebx
		push esi
		push edi

		mov esi, [esp+24]
		mov ebx, [esp+20]

		sub ecx, edx
		xor eax, eax

		sub eax, esi
		lea ebx, [ebx+4*esi]

		sar eax, 1		// clears the carry flag
		jz  loopend

} loopstart: __asm {
		mov    esi,[edx]
		mov    ebp,[edx+4]

		mov    edi,[ebx+8*eax]
		lea    edx,[edx+8]

		adc    esi,edi
		mov    edi,[ebx+8*eax+4]

		adc    ebp,edi
		inc    eax

		mov    [edx+ecx-8],esi
		mov    [edx+ecx-4],ebp

		jnz    loopstart

} loopend: __asm {
		adc eax, 0
		pop edi
		pop esi
		pop ebx
		pop ebp
		ret 8
	}
}

static /*__declspec(naked)*/ word __fastcall Subtract(word *C, const word *A, const word *B, unsigned int N)
{
	__asm
	{
		push ebp
		push ebx
		push esi
		push edi

		mov esi, [esp+24]
		mov ebx, [esp+20]

		sub ecx, edx
		xor eax, eax

		sub eax, esi
		lea ebx, [ebx+4*esi]

		sar eax, 1		// clears the carry flag
		jz  loopend

} loopstart: __asm {
		mov    esi,[edx]
		mov    ebp,[edx+4]

		mov    edi,[ebx+8*eax]
		lea    edx,[edx+8]

		sbb    esi,edi
		mov    edi,[ebx+8*eax+4]

		sbb    ebp,edi
		inc    eax

		mov    [edx+ecx-8],esi
		mov    [edx+ecx-4],ebp

		jnz    loopstart

} loopend: __asm {
		adc eax, 0
		pop edi
		pop esi
		pop ebx
		pop ebp
		ret 8
	}
}

#elif defined(__BORLANDC__)

word foo(word const*);
word foo2(unsigned int N);

// will use separately linked module
extern "C" {
word __fastcall Add(word *C, const word *A, const word *B, unsigned int N);
word __fastcall Subtract(word *C, const word *A, const word *B, unsigned int N);
};

word __fastcall Add(word *C, const word *A, const word *B, unsigned int N)
{
  foo(C);
  foo(A);
  foo(B);
  return foo2(N);
}

word __fastcall Subtract(word *C, const word *A, const word *B, unsigned int N)
{
  foo(C);
  foo(A);
  foo(B);
  return foo2(N);
}

#else	// defined(_MSC_VER) && defined(_M_IX86) && (_M_IX86<=500)

static word Add(word *C, const word *A, const word *B, unsigned int N)
{
	assert (N%2 == 0);

	word carry=0;
	for (unsigned i = 0; i < N; i+=2)
	{
		dword u = (dword) carry + A[i] + B[i];
		C[i] = LOW_WORD(u);
		u = (dword) HIGH_WORD(u) + A[i+1] + B[i+1];
		C[i+1] = LOW_WORD(u);
		carry = HIGH_WORD(u);
	}
	return carry;
}

static word Subtract(word *C, const word *A, const word *B, unsigned int N)
{
	assert (N%2 == 0);

	word borrow=0;
	for (unsigned i = 0; i < N; i+=2)
	{
		dword u = (dword) A[i] - B[i] - borrow;
		C[i] = LOW_WORD(u);
		u = (dword) A[i+1] - B[i+1] - (word)(0-HIGH_WORD(u));
		C[i+1] = LOW_WORD(u);
		borrow = 0-HIGH_WORD(u);
	}
	return borrow;
}

#endif	// defined(_MSC_VER) && defined(_M_IX86) && (_M_IX86<=500)