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Text File | 1993-03-06 | 7.0 KB | 377 lines

/* ** ** 80386 assembly primitives for RSA library ** GNU gas syntax, tested with gcc v1.39 ** ** Compile with UNIT32 defined, MULTUNIT must be unsigned long ** assemble this file with gcc -c (file should have .S suffix) ** ** Written by Branko Lankester (lankeste@fwi.uva.nl) 11/18/91 ** Last revised: 12/01/92 ** */ #ifndef SYSV #ifdef __STDC__ #define ENTRY(name) .align 4 ; .globl _##name ; _##name: #else #define ENTRY(name) .align 4 ; .globl _/**/name ; _/**/name: #endif #else /* SYSV */ #define ENTRY(name) .align 4 ; .globl name ; name: #endif .text /* ********************* set precision ******************** */ ENTRY (P_SETP) pushl %ebp movl %esp,%ebp pushl %ebx pushl %ecx pushl %edx movl 8(%ebp),%eax addl $0x1f,%eax shrl $5,%eax movl %eax,%ebx shrl $3,%eax movl %eax,prec8 andl $7,%ebx movl $add_ref,%eax movl %eax,%ecx subl $add_1ref,%eax mul %ebx subl %eax,%ecx movl %ecx,addp movl $sub_ref,%ecx subl %eax,%ecx movl %ecx,subp movl $rot_ref,%eax movl %eax,%ecx subl $rot_1ref,%eax mul %ebx subl %eax,%ecx movl %ecx,rotp movl $mul_ref,%eax movl %eax,%ecx subl $mul_1ref,%eax mul %ebx subl %eax,%ecx movl %ecx,mulp popl %edx popl %ecx popl %ebx leave ret /* ********************* mpi add with carry ******************** */ #define ADDU lodsl ; adcl %eax,(%ebx,%esi) ENTRY (P_ADDC) pushl %ebp movl %esp,%ebp pushl %ebx pushl %ecx pushl %esi pushl %edi movl 12(%ebp),%esi movl 8(%ebp),%ebx subl %esi,%ebx subl $4,%ebx cld movl 16(%ebp),%eax movl prec8,%ecx orl %ecx,%ecx rcrl $1,%eax /* set the carry flag */ jz add_units /* z-flag set by orl %ecx,%ecx */ add_8u: ADDU ; ADDU ; ADDU ; ADDU ; ADDU ; ADDU ; ADDU ; ADDU loop add_8u add_units: jmp *addp ADDU ; ADDU ; ADDU ; ADDU ; ADDU ; ADDU add_1ref: /* label to compute size of codes */ ADDU add_ref: rcll $1,%eax andl $1,%eax popl %edi popl %esi popl %ecx popl %ebx leave ret /* ********************* mpi subtract with borrow ******************** */ #define SUBU lodsl ; sbbl %eax,(%ebx,%esi) ENTRY (P_SUBB) pushl %ebp movl %esp,%ebp pushl %ebx pushl %ecx pushl %esi pushl %edi movl 12(%ebp),%esi movl 8(%ebp),%ebx subl %esi,%ebx subl $4,%ebx cld movl 16(%ebp),%eax movl prec8,%ecx orl %ecx,%ecx rcrl $1,%eax jz sub_units sub_8u: SUBU ; SUBU ; SUBU ; SUBU ; SUBU ; SUBU ; SUBU ; SUBU loop sub_8u sub_units: jmp *subp SUBU ; SUBU ; SUBU ; SUBU ; SUBU ; SUBU ; SUBU sub_ref: rcll $1,%eax andl $1,%eax popl %edi popl %esi popl %ecx popl %ebx leave ret /* ********************* mpi rotate left ******************** */ #define ROTU rcll $1,(%ebx,%esi,4) ; incl %esi ENTRY (P_ROTL) pushl %ebp movl %esp,%ebp pushl %ebx pushl %ecx pushl %esi movl 8(%ebp),%ebx movl 12(%ebp),%eax xorl %esi,%esi movl prec8,%ecx orl %ecx,%ecx rcrl $1,%eax /* set the carry flag */ jz rot_units /* z-flag set by orl %ecx,%ecx */ rot_8u: rcll $1,(%ebx) rcll $1,4(%ebx) rcll $1,8(%ebx) rcll $1,12(%ebx) rcll $1,16(%ebx) rcll $1,20(%ebx) rcll $1,24(%ebx) rcll $1,28(%ebx) leal 32(%ebx),%ebx loop rot_8u rot_units: jmp *rotp ROTU ; ROTU ; ROTU ; ROTU ; ROTU ; ROTU ; ROTU rot_1ref: ROTU rot_ref: rcll $1,%eax andl $1,%eax popl %esi popl %ecx popl %ebx leave ret /* ********************* mpi multiply ******************** */ #define MULU \ lodsl ; \ mull %ebp ; \ addl %ebx,%eax ; \ adcl $0,%edx ; \ addl (%edi),%eax ; \ adcl $0,%edx ; \ movl %edx,%ebx ; \ stosl ENTRY (P_SMULA) pushl %ebp movl %esp,%ebp pushl %ebx pushl %ecx pushl %edx pushl %esi pushl %edi xorl %ebx,%ebx movl prec8,%ecx movl 8(%ebp),%edi movl 12(%ebp),%esi movl 16(%ebp),%ebp cld orl %ecx,%ecx jz mul_units mul_8u: MULU ; MULU ; MULU ; MULU ; MULU ; MULU ; MULU ; MULU decl %ecx jnz mul_8u /* offset too big for loop */ mul_units: jmp *mulp MULU ; MULU ; MULU ; MULU ; MULU ; MULU mul_1ref: MULU mul_ref: addl %ebx,(%edi) popl %edi popl %esi popl %edx popl %ecx popl %ebx popl %ebp ret .lcomm _reciph,4 .lcomm _recipl,4 .lcomm _mshift,4 ENTRY (p_setrecip) movl 4(%esp),%eax movl %eax,_reciph movl 8(%esp),%eax movl %eax,_recipl movl 12(%esp),%eax movl %eax,_mshift ret ENTRY (p_quo_digit) pushl %ebp pushl %ebx pushl %esi pushl %edi movl 20(%esp),%esi /* dividend */ movl -8(%esi),%eax /* dividend[-2] */ notl %eax mull _reciph addl _reciph,%eax adcl $0,%edx movl %eax,%ebx movl %edx,%edi /* di:bx = q1 */ movl -4(%esi),%eax /* dividend[-1] */ notl %eax mull _recipl incl %edx /* dx:ax = q2 */ movl %edx,%ebp andl %edi,%ebp andl $1,%ebp /* bp = lsb_factor */ addl %ebx,%eax adcl %edx,%edi rcrl $1,%edi /* di = MS word of q0 */ movl -4(%esi),%eax /* dividend [-1] */ notl %eax mull _reciph movl %eax,%ebx movl %edx,%ecx /* cx:bx = q1 */ movl (%esi),%eax /* dividend[0] */ notl %eax mull _recipl /* dx:ax = q2 */ xorl %ebx,%eax andl %eax,%ebp /* lsb correction */ xorl %ebx,%eax /* restore ax */ addl %ebx,%eax adcl %ecx,%edx rcrl $1,%edx rcrl $1,%eax /* dx:ax = q */ addl %edi,%eax /* + scaled q0 */ adcl $0,%edx addl %ebp,%eax /* + lsb correction */ adcl $0,%edx /* q */ shll $1,%eax rcll $1,%edx rcll $1,%eax rcll $1,%edx rcll $1,%eax andl $3,%eax movl %eax,%ecx movl %edx,%ebx /* bx:cx = q >> 14 */ movl (%esi),%eax /* dividend[0] */ notl %eax mull _reciph shll $1,%eax rcll $1,%edx addl %ebx,%eax adcl %ecx,%edx /* q */ movl _mshift,%ecx cmpl $32,_mshift je L2 #if 0 shrl %cl,%eax movl %edx,%ebx shrl %cl,%edx negl %ecx addl $32,%ecx shll %cl,%ebx addl %ebx,%eax /* dx:ax = q >> mshift */ #else #ifdef SYSV shrdl %edx,%eax #else shrdl %cl,%edx,%eax #endif shrl %cl,%edx #endif orl %edx,%edx je L1 movl $-1,%eax jmp L1 L2: xchgl %edx,%eax L1: popl %edi popl %esi popl %ebx popl %ebp ret .lcomm prec8,4 .lcomm addp,4 .lcomm subp,4 .lcomm rotp,4 .lcomm mulp,4