ref: 98c1cd7ae022efe276123898af6b892eade0732c
dir: /third_party/boringssl/src/crypto/fipsmodule/modes/asm/ghashp8-ppc.pl/
#! /usr/bin/env perl # Copyright 2014-2016 The OpenSSL Project Authors. All Rights Reserved. # # Licensed under the OpenSSL license (the "License"). You may not use # this file except in compliance with the License. You can obtain a copy # in the file LICENSE in the source distribution or at # https://www.openssl.org/source/license.html # # ==================================================================== # Written by Andy Polyakov <appro@openssl.org> for the OpenSSL # project. The module is, however, dual licensed under OpenSSL and # CRYPTOGAMS licenses depending on where you obtain it. For further # details see http://www.openssl.org/~appro/cryptogams/. # ==================================================================== # # GHASH for for PowerISA v2.07. # # July 2014 # # Accurate performance measurements are problematic, because it's # always virtualized setup with possibly throttled processor. # Relative comparison is therefore more informative. This initial # version is ~2.1x slower than hardware-assisted AES-128-CTR, ~12x # faster than "4-bit" integer-only compiler-generated 64-bit code. # "Initial version" means that there is room for futher improvement. # May 2016 # # 2x aggregated reduction improves performance by 50% (resulting # performance on POWER8 is 1 cycle per processed byte), and 4x # aggregated reduction - by 170% or 2.7x (resulting in 0.55 cpb). $flavour=shift; $output =shift; if ($flavour =~ /64/) { $SIZE_T=8; $LRSAVE=2*$SIZE_T; $STU="stdu"; $POP="ld"; $PUSH="std"; $UCMP="cmpld"; $SHRI="srdi"; } elsif ($flavour =~ /32/) { $SIZE_T=4; $LRSAVE=$SIZE_T; $STU="stwu"; $POP="lwz"; $PUSH="stw"; $UCMP="cmplw"; $SHRI="srwi"; } else { die "nonsense $flavour"; } $sp="r1"; $FRAME=6*$SIZE_T+13*16; # 13*16 is for v20-v31 offload $0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1; ( $xlate="${dir}ppc-xlate.pl" and -f $xlate ) or ( $xlate="${dir}../../../perlasm/ppc-xlate.pl" and -f $xlate) or die "can't locate ppc-xlate.pl"; open STDOUT,"| $^X \"$xlate\" $flavour \"$output\"" || die "can't call $xlate: $!"; my ($Xip,$Htbl,$inp,$len)=map("r$_",(3..6)); # argument block my ($Xl,$Xm,$Xh,$IN)=map("v$_",(0..3)); my ($zero,$t0,$t1,$t2,$xC2,$H,$Hh,$Hl,$lemask)=map("v$_",(4..12)); my ($Xl1,$Xm1,$Xh1,$IN1,$H2,$H2h,$H2l)=map("v$_",(13..19)); my $vrsave="r12"; $code=<<___; .machine "any" .text .globl .gcm_init_p8 .align 5 .gcm_init_p8: li r0,-4096 li r8,0x10 mfspr $vrsave,256 li r9,0x20 mtspr 256,r0 li r10,0x30 lvx_u $H,0,r4 # load H vspltisb $xC2,-16 # 0xf0 vspltisb $t0,1 # one vaddubm $xC2,$xC2,$xC2 # 0xe0 vxor $zero,$zero,$zero vor $xC2,$xC2,$t0 # 0xe1 vsldoi $xC2,$xC2,$zero,15 # 0xe1... vsldoi $t1,$zero,$t0,1 # ...1 vaddubm $xC2,$xC2,$xC2 # 0xc2... vspltisb $t2,7 vor $xC2,$xC2,$t1 # 0xc2....01 vspltb $t1,$H,0 # most significant byte vsl $H,$H,$t0 # H<<=1 vsrab $t1,$t1,$t2 # broadcast carry bit vand $t1,$t1,$xC2 vxor $IN,$H,$t1 # twisted H vsldoi $H,$IN,$IN,8 # twist even more ... vsldoi $xC2,$zero,$xC2,8 # 0xc2.0 vsldoi $Hl,$zero,$H,8 # ... and split vsldoi $Hh,$H,$zero,8 stvx_u $xC2,0,r3 # save pre-computed table stvx_u $Hl,r8,r3 li r8,0x40 stvx_u $H, r9,r3 li r9,0x50 stvx_u $Hh,r10,r3 li r10,0x60 vpmsumd $Xl,$IN,$Hl # H.lo·H.lo vpmsumd $Xm,$IN,$H # H.hi·H.lo+H.lo·H.hi vpmsumd $Xh,$IN,$Hh # H.hi·H.hi vpmsumd $t2,$Xl,$xC2 # 1st reduction phase vsldoi $t0,$Xm,$zero,8 vsldoi $t1,$zero,$Xm,8 vxor $Xl,$Xl,$t0 vxor $Xh,$Xh,$t1 vsldoi $Xl,$Xl,$Xl,8 vxor $Xl,$Xl,$t2 vsldoi $t1,$Xl,$Xl,8 # 2nd reduction phase vpmsumd $Xl,$Xl,$xC2 vxor $t1,$t1,$Xh vxor $IN1,$Xl,$t1 vsldoi $H2,$IN1,$IN1,8 vsldoi $H2l,$zero,$H2,8 vsldoi $H2h,$H2,$zero,8 stvx_u $H2l,r8,r3 # save H^2 li r8,0x70 stvx_u $H2,r9,r3 li r9,0x80 stvx_u $H2h,r10,r3 li r10,0x90 ___ { my ($t4,$t5,$t6) = ($Hl,$H,$Hh); $code.=<<___; vpmsumd $Xl,$IN,$H2l # H.lo·H^2.lo vpmsumd $Xl1,$IN1,$H2l # H^2.lo·H^2.lo vpmsumd $Xm,$IN,$H2 # H.hi·H^2.lo+H.lo·H^2.hi vpmsumd $Xm1,$IN1,$H2 # H^2.hi·H^2.lo+H^2.lo·H^2.hi vpmsumd $Xh,$IN,$H2h # H.hi·H^2.hi vpmsumd $Xh1,$IN1,$H2h # H^2.hi·H^2.hi vpmsumd $t2,$Xl,$xC2 # 1st reduction phase vpmsumd $t6,$Xl1,$xC2 # 1st reduction phase vsldoi $t0,$Xm,$zero,8 vsldoi $t1,$zero,$Xm,8 vsldoi $t4,$Xm1,$zero,8 vsldoi $t5,$zero,$Xm1,8 vxor $Xl,$Xl,$t0 vxor $Xh,$Xh,$t1 vxor $Xl1,$Xl1,$t4 vxor $Xh1,$Xh1,$t5 vsldoi $Xl,$Xl,$Xl,8 vsldoi $Xl1,$Xl1,$Xl1,8 vxor $Xl,$Xl,$t2 vxor $Xl1,$Xl1,$t6 vsldoi $t1,$Xl,$Xl,8 # 2nd reduction phase vsldoi $t5,$Xl1,$Xl1,8 # 2nd reduction phase vpmsumd $Xl,$Xl,$xC2 vpmsumd $Xl1,$Xl1,$xC2 vxor $t1,$t1,$Xh vxor $t5,$t5,$Xh1 vxor $Xl,$Xl,$t1 vxor $Xl1,$Xl1,$t5 vsldoi $H,$Xl,$Xl,8 vsldoi $H2,$Xl1,$Xl1,8 vsldoi $Hl,$zero,$H,8 vsldoi $Hh,$H,$zero,8 vsldoi $H2l,$zero,$H2,8 vsldoi $H2h,$H2,$zero,8 stvx_u $Hl,r8,r3 # save H^3 li r8,0xa0 stvx_u $H,r9,r3 li r9,0xb0 stvx_u $Hh,r10,r3 li r10,0xc0 stvx_u $H2l,r8,r3 # save H^4 stvx_u $H2,r9,r3 stvx_u $H2h,r10,r3 mtspr 256,$vrsave blr .long 0 .byte 0,12,0x14,0,0,0,2,0 .long 0 .size .gcm_init_p8,.-.gcm_init_p8 ___ } $code.=<<___; .globl .gcm_gmult_p8 .align 5 .gcm_gmult_p8: lis r0,0xfff8 li r8,0x10 mfspr $vrsave,256 li r9,0x20 mtspr 256,r0 li r10,0x30 lvx_u $IN,0,$Xip # load Xi lvx_u $Hl,r8,$Htbl # load pre-computed table le?lvsl $lemask,r0,r0 lvx_u $H, r9,$Htbl le?vspltisb $t0,0x07 lvx_u $Hh,r10,$Htbl le?vxor $lemask,$lemask,$t0 lvx_u $xC2,0,$Htbl le?vperm $IN,$IN,$IN,$lemask vxor $zero,$zero,$zero vpmsumd $Xl,$IN,$Hl # H.lo·Xi.lo vpmsumd $Xm,$IN,$H # H.hi·Xi.lo+H.lo·Xi.hi vpmsumd $Xh,$IN,$Hh # H.hi·Xi.hi vpmsumd $t2,$Xl,$xC2 # 1st reduction phase vsldoi $t0,$Xm,$zero,8 vsldoi $t1,$zero,$Xm,8 vxor $Xl,$Xl,$t0 vxor $Xh,$Xh,$t1 vsldoi $Xl,$Xl,$Xl,8 vxor $Xl,$Xl,$t2 vsldoi $t1,$Xl,$Xl,8 # 2nd reduction phase vpmsumd $Xl,$Xl,$xC2 vxor $t1,$t1,$Xh vxor $Xl,$Xl,$t1 le?vperm $Xl,$Xl,$Xl,$lemask stvx_u $Xl,0,$Xip # write out Xi mtspr 256,$vrsave blr .long 0 .byte 0,12,0x14,0,0,0,2,0 .long 0 .size .gcm_gmult_p8,.-.gcm_gmult_p8 .globl .gcm_ghash_p8 .align 5 .gcm_ghash_p8: li r0,-4096 li r8,0x10 mfspr $vrsave,256 li r9,0x20 mtspr 256,r0 li r10,0x30 lvx_u $Xl,0,$Xip # load Xi lvx_u $Hl,r8,$Htbl # load pre-computed table li r8,0x40 le?lvsl $lemask,r0,r0 lvx_u $H, r9,$Htbl li r9,0x50 le?vspltisb $t0,0x07 lvx_u $Hh,r10,$Htbl li r10,0x60 le?vxor $lemask,$lemask,$t0 lvx_u $xC2,0,$Htbl le?vperm $Xl,$Xl,$Xl,$lemask vxor $zero,$zero,$zero ${UCMP}i $len,64 bge Lgcm_ghash_p8_4x lvx_u $IN,0,$inp addi $inp,$inp,16 subic. $len,$len,16 le?vperm $IN,$IN,$IN,$lemask vxor $IN,$IN,$Xl beq Lshort lvx_u $H2l,r8,$Htbl # load H^2 li r8,16 lvx_u $H2, r9,$Htbl add r9,$inp,$len # end of input lvx_u $H2h,r10,$Htbl be?b Loop_2x .align 5 Loop_2x: lvx_u $IN1,0,$inp le?vperm $IN1,$IN1,$IN1,$lemask subic $len,$len,32 vpmsumd $Xl,$IN,$H2l # H^2.lo·Xi.lo vpmsumd $Xl1,$IN1,$Hl # H.lo·Xi+1.lo subfe r0,r0,r0 # borrow?-1:0 vpmsumd $Xm,$IN,$H2 # H^2.hi·Xi.lo+H^2.lo·Xi.hi vpmsumd $Xm1,$IN1,$H # H.hi·Xi+1.lo+H.lo·Xi+1.hi and r0,r0,$len vpmsumd $Xh,$IN,$H2h # H^2.hi·Xi.hi vpmsumd $Xh1,$IN1,$Hh # H.hi·Xi+1.hi add $inp,$inp,r0 vxor $Xl,$Xl,$Xl1 vxor $Xm,$Xm,$Xm1 vpmsumd $t2,$Xl,$xC2 # 1st reduction phase vsldoi $t0,$Xm,$zero,8 vsldoi $t1,$zero,$Xm,8 vxor $Xh,$Xh,$Xh1 vxor $Xl,$Xl,$t0 vxor $Xh,$Xh,$t1 vsldoi $Xl,$Xl,$Xl,8 vxor $Xl,$Xl,$t2 lvx_u $IN,r8,$inp addi $inp,$inp,32 vsldoi $t1,$Xl,$Xl,8 # 2nd reduction phase vpmsumd $Xl,$Xl,$xC2 le?vperm $IN,$IN,$IN,$lemask vxor $t1,$t1,$Xh vxor $IN,$IN,$t1 vxor $IN,$IN,$Xl $UCMP r9,$inp bgt Loop_2x # done yet? cmplwi $len,0 bne Leven Lshort: vpmsumd $Xl,$IN,$Hl # H.lo·Xi.lo vpmsumd $Xm,$IN,$H # H.hi·Xi.lo+H.lo·Xi.hi vpmsumd $Xh,$IN,$Hh # H.hi·Xi.hi vpmsumd $t2,$Xl,$xC2 # 1st reduction phase vsldoi $t0,$Xm,$zero,8 vsldoi $t1,$zero,$Xm,8 vxor $Xl,$Xl,$t0 vxor $Xh,$Xh,$t1 vsldoi $Xl,$Xl,$Xl,8 vxor $Xl,$Xl,$t2 vsldoi $t1,$Xl,$Xl,8 # 2nd reduction phase vpmsumd $Xl,$Xl,$xC2 vxor $t1,$t1,$Xh Leven: vxor $Xl,$Xl,$t1 le?vperm $Xl,$Xl,$Xl,$lemask stvx_u $Xl,0,$Xip # write out Xi mtspr 256,$vrsave blr .long 0 .byte 0,12,0x14,0,0,0,4,0 .long 0 ___ { my ($Xl3,$Xm2,$IN2,$H3l,$H3,$H3h, $Xh3,$Xm3,$IN3,$H4l,$H4,$H4h) = map("v$_",(20..31)); my $IN0=$IN; my ($H21l,$H21h,$loperm,$hiperm) = ($Hl,$Hh,$H2l,$H2h); $code.=<<___; .align 5 .gcm_ghash_p8_4x: Lgcm_ghash_p8_4x: $STU $sp,-$FRAME($sp) li r10,`15+6*$SIZE_T` li r11,`31+6*$SIZE_T` stvx v20,r10,$sp addi r10,r10,32 stvx v21,r11,$sp addi r11,r11,32 stvx v22,r10,$sp addi r10,r10,32 stvx v23,r11,$sp addi r11,r11,32 stvx v24,r10,$sp addi r10,r10,32 stvx v25,r11,$sp addi r11,r11,32 stvx v26,r10,$sp addi r10,r10,32 stvx v27,r11,$sp addi r11,r11,32 stvx v28,r10,$sp addi r10,r10,32 stvx v29,r11,$sp addi r11,r11,32 stvx v30,r10,$sp li r10,0x60 stvx v31,r11,$sp li r0,-1 stw $vrsave,`$FRAME-4`($sp) # save vrsave mtspr 256,r0 # preserve all AltiVec registers lvsl $t0,0,r8 # 0x0001..0e0f #lvx_u $H2l,r8,$Htbl # load H^2 li r8,0x70 lvx_u $H2, r9,$Htbl li r9,0x80 vspltisb $t1,8 # 0x0808..0808 #lvx_u $H2h,r10,$Htbl li r10,0x90 lvx_u $H3l,r8,$Htbl # load H^3 li r8,0xa0 lvx_u $H3, r9,$Htbl li r9,0xb0 lvx_u $H3h,r10,$Htbl li r10,0xc0 lvx_u $H4l,r8,$Htbl # load H^4 li r8,0x10 lvx_u $H4, r9,$Htbl li r9,0x20 lvx_u $H4h,r10,$Htbl li r10,0x30 vsldoi $t2,$zero,$t1,8 # 0x0000..0808 vaddubm $hiperm,$t0,$t2 # 0x0001..1617 vaddubm $loperm,$t1,$hiperm # 0x0809..1e1f $SHRI $len,$len,4 # this allows to use sign bit # as carry lvx_u $IN0,0,$inp # load input lvx_u $IN1,r8,$inp subic. $len,$len,8 lvx_u $IN2,r9,$inp lvx_u $IN3,r10,$inp addi $inp,$inp,0x40 le?vperm $IN0,$IN0,$IN0,$lemask le?vperm $IN1,$IN1,$IN1,$lemask le?vperm $IN2,$IN2,$IN2,$lemask le?vperm $IN3,$IN3,$IN3,$lemask vxor $Xh,$IN0,$Xl vpmsumd $Xl1,$IN1,$H3l vpmsumd $Xm1,$IN1,$H3 vpmsumd $Xh1,$IN1,$H3h vperm $H21l,$H2,$H,$hiperm vperm $t0,$IN2,$IN3,$loperm vperm $H21h,$H2,$H,$loperm vperm $t1,$IN2,$IN3,$hiperm vpmsumd $Xm2,$IN2,$H2 # H^2.lo·Xi+2.hi+H^2.hi·Xi+2.lo vpmsumd $Xl3,$t0,$H21l # H^2.lo·Xi+2.lo+H.lo·Xi+3.lo vpmsumd $Xm3,$IN3,$H # H.hi·Xi+3.lo +H.lo·Xi+3.hi vpmsumd $Xh3,$t1,$H21h # H^2.hi·Xi+2.hi+H.hi·Xi+3.hi vxor $Xm2,$Xm2,$Xm1 vxor $Xl3,$Xl3,$Xl1 vxor $Xm3,$Xm3,$Xm2 vxor $Xh3,$Xh3,$Xh1 blt Ltail_4x Loop_4x: lvx_u $IN0,0,$inp lvx_u $IN1,r8,$inp subic. $len,$len,4 lvx_u $IN2,r9,$inp lvx_u $IN3,r10,$inp addi $inp,$inp,0x40 le?vperm $IN1,$IN1,$IN1,$lemask le?vperm $IN2,$IN2,$IN2,$lemask le?vperm $IN3,$IN3,$IN3,$lemask le?vperm $IN0,$IN0,$IN0,$lemask vpmsumd $Xl,$Xh,$H4l # H^4.lo·Xi.lo vpmsumd $Xm,$Xh,$H4 # H^4.hi·Xi.lo+H^4.lo·Xi.hi vpmsumd $Xh,$Xh,$H4h # H^4.hi·Xi.hi vpmsumd $Xl1,$IN1,$H3l vpmsumd $Xm1,$IN1,$H3 vpmsumd $Xh1,$IN1,$H3h vxor $Xl,$Xl,$Xl3 vxor $Xm,$Xm,$Xm3 vxor $Xh,$Xh,$Xh3 vperm $t0,$IN2,$IN3,$loperm vperm $t1,$IN2,$IN3,$hiperm vpmsumd $t2,$Xl,$xC2 # 1st reduction phase vpmsumd $Xl3,$t0,$H21l # H.lo·Xi+3.lo +H^2.lo·Xi+2.lo vpmsumd $Xh3,$t1,$H21h # H.hi·Xi+3.hi +H^2.hi·Xi+2.hi vsldoi $t0,$Xm,$zero,8 vsldoi $t1,$zero,$Xm,8 vxor $Xl,$Xl,$t0 vxor $Xh,$Xh,$t1 vsldoi $Xl,$Xl,$Xl,8 vxor $Xl,$Xl,$t2 vsldoi $t1,$Xl,$Xl,8 # 2nd reduction phase vpmsumd $Xm2,$IN2,$H2 # H^2.hi·Xi+2.lo+H^2.lo·Xi+2.hi vpmsumd $Xm3,$IN3,$H # H.hi·Xi+3.lo +H.lo·Xi+3.hi vpmsumd $Xl,$Xl,$xC2 vxor $Xl3,$Xl3,$Xl1 vxor $Xh3,$Xh3,$Xh1 vxor $Xh,$Xh,$IN0 vxor $Xm2,$Xm2,$Xm1 vxor $Xh,$Xh,$t1 vxor $Xm3,$Xm3,$Xm2 vxor $Xh,$Xh,$Xl bge Loop_4x Ltail_4x: vpmsumd $Xl,$Xh,$H4l # H^4.lo·Xi.lo vpmsumd $Xm,$Xh,$H4 # H^4.hi·Xi.lo+H^4.lo·Xi.hi vpmsumd $Xh,$Xh,$H4h # H^4.hi·Xi.hi vxor $Xl,$Xl,$Xl3 vxor $Xm,$Xm,$Xm3 vpmsumd $t2,$Xl,$xC2 # 1st reduction phase vsldoi $t0,$Xm,$zero,8 vsldoi $t1,$zero,$Xm,8 vxor $Xh,$Xh,$Xh3 vxor $Xl,$Xl,$t0 vxor $Xh,$Xh,$t1 vsldoi $Xl,$Xl,$Xl,8 vxor $Xl,$Xl,$t2 vsldoi $t1,$Xl,$Xl,8 # 2nd reduction phase vpmsumd $Xl,$Xl,$xC2 vxor $t1,$t1,$Xh vxor $Xl,$Xl,$t1 addic. $len,$len,4 beq Ldone_4x lvx_u $IN0,0,$inp ${UCMP}i $len,2 li $len,-4 blt Lone lvx_u $IN1,r8,$inp beq Ltwo Lthree: lvx_u $IN2,r9,$inp le?vperm $IN0,$IN0,$IN0,$lemask le?vperm $IN1,$IN1,$IN1,$lemask le?vperm $IN2,$IN2,$IN2,$lemask vxor $Xh,$IN0,$Xl vmr $H4l,$H3l vmr $H4, $H3 vmr $H4h,$H3h vperm $t0,$IN1,$IN2,$loperm vperm $t1,$IN1,$IN2,$hiperm vpmsumd $Xm2,$IN1,$H2 # H^2.lo·Xi+1.hi+H^2.hi·Xi+1.lo vpmsumd $Xm3,$IN2,$H # H.hi·Xi+2.lo +H.lo·Xi+2.hi vpmsumd $Xl3,$t0,$H21l # H^2.lo·Xi+1.lo+H.lo·Xi+2.lo vpmsumd $Xh3,$t1,$H21h # H^2.hi·Xi+1.hi+H.hi·Xi+2.hi vxor $Xm3,$Xm3,$Xm2 b Ltail_4x .align 4 Ltwo: le?vperm $IN0,$IN0,$IN0,$lemask le?vperm $IN1,$IN1,$IN1,$lemask vxor $Xh,$IN0,$Xl vperm $t0,$zero,$IN1,$loperm vperm $t1,$zero,$IN1,$hiperm vsldoi $H4l,$zero,$H2,8 vmr $H4, $H2 vsldoi $H4h,$H2,$zero,8 vpmsumd $Xl3,$t0, $H21l # H.lo·Xi+1.lo vpmsumd $Xm3,$IN1,$H # H.hi·Xi+1.lo+H.lo·Xi+2.hi vpmsumd $Xh3,$t1, $H21h # H.hi·Xi+1.hi b Ltail_4x .align 4 Lone: le?vperm $IN0,$IN0,$IN0,$lemask vsldoi $H4l,$zero,$H,8 vmr $H4, $H vsldoi $H4h,$H,$zero,8 vxor $Xh,$IN0,$Xl vxor $Xl3,$Xl3,$Xl3 vxor $Xm3,$Xm3,$Xm3 vxor $Xh3,$Xh3,$Xh3 b Ltail_4x Ldone_4x: le?vperm $Xl,$Xl,$Xl,$lemask stvx_u $Xl,0,$Xip # write out Xi li r10,`15+6*$SIZE_T` li r11,`31+6*$SIZE_T` mtspr 256,$vrsave lvx v20,r10,$sp addi r10,r10,32 lvx v21,r11,$sp addi r11,r11,32 lvx v22,r10,$sp addi r10,r10,32 lvx v23,r11,$sp addi r11,r11,32 lvx v24,r10,$sp addi r10,r10,32 lvx v25,r11,$sp addi r11,r11,32 lvx v26,r10,$sp addi r10,r10,32 lvx v27,r11,$sp addi r11,r11,32 lvx v28,r10,$sp addi r10,r10,32 lvx v29,r11,$sp addi r11,r11,32 lvx v30,r10,$sp lvx v31,r11,$sp addi $sp,$sp,$FRAME blr .long 0 .byte 0,12,0x04,0,0x80,0,4,0 .long 0 ___ } $code.=<<___; .size .gcm_ghash_p8,.-.gcm_ghash_p8 .asciz "GHASH for PowerISA 2.07, CRYPTOGAMS by <appro\@openssl.org>" .align 2 ___ foreach (split("\n",$code)) { s/\`([^\`]*)\`/eval $1/geo; if ($flavour =~ /le$/o) { # little-endian s/le\?//o or s/be\?/#be#/o; } else { s/le\?/#le#/o or s/be\?//o; } print $_,"\n"; } close STDOUT or die "error closing STDOUT: $!"; # enforce flush