232 lines
5.5 KiB
ArmAsm
232 lines
5.5 KiB
ArmAsm
.file "reg_u_add.S"
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/*
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* reg_u_add.S
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*
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* Add two valid (TW_Valid) FPU_REG numbers, of the same sign, and put the
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* result in a destination FPU_REG.
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*
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* Call from C as:
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* void reg_u_add(FPU_REG *arg1, FPU_REG *arg2, FPU_REG *answ,
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* int control_w)
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*
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*
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* Copyright (C) 1992, 1993 W. Metzenthen, 22 Parker St, Ormond,
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* Vic 3163, Australia.
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* E-mail apm233m@vaxc.cc.monash.edu.au
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* All rights reserved.
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*
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* This copyright notice covers the redistribution and use of the
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* FPU emulator developed by W. Metzenthen. It covers only its use
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* in the 386BSD operating system. Any other use is not permitted
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* under this copyright.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must include information specifying
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* that source code for the emulator is freely available and include
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* either:
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* a) an offer to provide the source code for a nominal distribution
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* fee, or
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* b) list at least two alternative methods whereby the source
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* can be obtained, e.g. a publically accessible bulletin board
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* and an anonymous ftp site from which the software can be
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* downloaded.
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* 3. All advertising materials specifically mentioning features or use of
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* this emulator must acknowledge that it was developed by W. Metzenthen.
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* 4. The name of W. Metzenthen may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* W. METZENTHEN BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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/*
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| Kernel addition routine reg_u_add(reg *arg1, reg *arg2, reg *answ).
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| Takes two valid reg f.p. numbers (TW_Valid), which are
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| treated as unsigned numbers,
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| and returns their sum as a TW_Valid or TW_S f.p. number.
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| The returned number is normalized.
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| Basic checks are performed if PARANOID is defined.
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*/
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#include "exception.h"
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#include "fpu_asm.h"
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#include "control_w.h"
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.text
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.align 2,144
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.globl _reg_u_add
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_reg_u_add:
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pushl %ebp
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movl %esp,%ebp
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/* subl $16,%esp*/
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pushl %esi
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pushl %edi
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pushl %ebx
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movl PARAM1,%esi /* source 1 */
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movl PARAM2,%edi /* source 2 */
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#ifdef DENORM_OPERAND
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cmpl EXP_UNDER,EXP(%esi)
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jg xOp1_not_denorm
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call _denormal_operand
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orl %eax,%eax
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jnz FPU_Arith_exit
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xOp1_not_denorm:
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cmpl EXP_UNDER,EXP(%edi)
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jg xOp2_not_denorm
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call _denormal_operand
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orl %eax,%eax
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jnz FPU_Arith_exit
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xOp2_not_denorm:
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#endif DENORM_OPERAND
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/* xorl %ecx,%ecx*/
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movl EXP(%esi),%ecx
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subl EXP(%edi),%ecx /* exp1 - exp2 */
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/* jnc L_arg1_larger*/
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jge L_arg1_larger
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/* num1 is smaller */
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movl SIGL(%esi),%ebx
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movl SIGH(%esi),%eax
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movl %edi,%esi
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negw %cx
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jmp L_accum_loaded
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L_arg1_larger:
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/* num1 has larger or equal exponent */
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movl SIGL(%edi),%ebx
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movl SIGH(%edi),%eax
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L_accum_loaded:
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movl PARAM3,%edi /* destination */
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movb SIGN(%esi),%dl
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movb %dl,SIGN(%edi) /* Copy the sign from the first arg */
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movl EXP(%esi),%edx
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movl %edx,EXP(%edi) /* Copy exponent to destination */
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xorl %edx,%edx /* clear the extension */
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#ifdef PARANOID
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testl $0x80000000,%eax
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je L_bugged
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testl $0x80000000,SIGH(%esi)
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je L_bugged
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#endif PARANOID
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/* The number to be shifted is in %eax:%ebx:%edx*/
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cmpw $32,%cx /* shrd only works for 0..31 bits */
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jnc L_more_than_31
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/* less than 32 bits */
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shrd %cl,%ebx,%edx
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shrd %cl,%eax,%ebx
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shr %cl,%eax
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jmp L_shift_done
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L_more_than_31:
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cmpw $64,%cx
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jnc L_more_than_63
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subb $32,%cl
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jz L_exactly_32
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shrd %cl,%eax,%edx
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shr %cl,%eax
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orl %ebx,%ebx
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jz L_more_31_no_low /* none of the lowest bits is set*/
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orl $1,%edx /* record the fact in the extension*/
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L_more_31_no_low:
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movl %eax,%ebx
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xorl %eax,%eax
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jmp L_shift_done
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L_exactly_32:
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movl %ebx,%edx
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movl %eax,%ebx
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xorl %eax,%eax
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jmp L_shift_done
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L_more_than_63:
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cmpw $65,%cx
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jnc L_more_than_64
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movl %eax,%edx
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orl %ebx,%ebx
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jz L_more_63_no_low
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orl $1,%edx
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jmp L_more_63_no_low
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L_more_than_64:
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movl $1,%edx /* The shifted nr always at least one '1'*/
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L_more_63_no_low:
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xorl %ebx,%ebx
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xorl %eax,%eax
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L_shift_done:
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/* Now do the addition */
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addl SIGL(%esi),%ebx
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adcl SIGH(%esi),%eax
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jnc L_round_the_result
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/* Overflow, adjust the result */
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rcrl $1,%eax
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rcrl $1,%ebx
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rcrl $1,%edx
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jnc L_no_bit_lost
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orl $1,%edx
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L_no_bit_lost:
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incl EXP(%edi)
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L_round_the_result:
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jmp FPU_round /* Round the result*/
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#ifdef PARANOID
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/* If we ever get here then we have problems! */
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L_bugged:
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pushl EX_INTERNAL|0x201
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call EXCEPTION
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pop %ebx
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jmp L_exit
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#endif PARANOID
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L_exit:
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popl %ebx
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popl %edi
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popl %esi
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leave
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ret
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