276 lines
7.3 KiB
Prolog
276 lines
7.3 KiB
Prolog
#!/usr/bin/env perl
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#
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# ====================================================================
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# Written by Andy Polyakov <appro@openssl.org> for the OpenSSL
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# project. The module is, however, dual licensed under OpenSSL and
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# CRYPTOGAMS licenses depending on where you obtain it. For further
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# details see http://www.openssl.org/~appro/cryptogams/.
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# ====================================================================
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#
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# April 2010
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#
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# The module implements "4-bit" GCM GHASH function and underlying
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# single multiplication operation in GF(2^128). "4-bit" means that it
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# uses 256 bytes per-key table [+32 bytes shared table]. There is no
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# experimental performance data available yet. The only approximation
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# that can be made at this point is based on code size. Inner loop is
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# 32 instructions long and on single-issue core should execute in <40
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# cycles. Having verified that gcc 3.4 didn't unroll corresponding
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# loop, this assembler loop body was found to be ~3x smaller than
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# compiler-generated one...
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#
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# Note about "528B" variant. In ARM case it makes lesser sense to
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# implement it for following reasons:
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#
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# - performance improvement won't be anywhere near 50%, because 128-
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# bit shift operation is neatly fused with 128-bit xor here, and
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# "538B" variant would eliminate only 4-5 instructions out of 32
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# in the inner loop (meaning that estimated improvement is ~15%);
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# - ARM-based systems are often embedded ones and extra memory
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# consumption might be unappreciated (for so little improvement);
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#
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# Byte order [in]dependence. =========================================
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#
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# Caller is expected to maintain specific *dword* order in Htable,
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# namely with *least* significant dword of 128-bit value at *lower*
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# address. This differs completely from C code and has everything to
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# do with ldm instruction and order in which dwords are "consumed" by
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# algorithm. *Byte* order within these dwords in turn is whatever
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# *native* byte order on current platform. See gcm128.c for working
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# example...
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while (($output=shift) && ($output!~/^\w[\w\-]*\.\w+$/)) {}
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open STDOUT,">$output";
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$Xi="r0"; # argument block
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$Htbl="r1";
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$inp="r2";
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$len="r3";
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$Zll="r4"; # variables
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$Zlh="r5";
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$Zhl="r6";
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$Zhh="r7";
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$Tll="r8";
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$Tlh="r9";
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$Thl="r10";
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$Thh="r11";
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$nlo="r12";
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################# r13 is stack pointer
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$nhi="r14";
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################# r15 is program counter
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$rem_4bit=$inp; # used in gcm_gmult_4bit
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$cnt=$len;
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sub Zsmash() {
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my $i=12;
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my @args=@_;
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for ($Zll,$Zlh,$Zhl,$Zhh) {
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# can be reduced to single "str $_,[$Xi,$i]" on big-endian platforms
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$code.=<<___;
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mov $Tlh,$_,lsr#8
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strb $_,[$Xi,#$i+3]
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mov $Thl,$_,lsr#16
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strb $Tlh,[$Xi,#$i+2]
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mov $Thh,$_,lsr#24
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strb $Thl,[$Xi,#$i+1]
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strb $Thh,[$Xi,#$i]
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___
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$code.="\t".shift(@args)."\n";
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$i-=4;
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}
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}
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$code=<<___;
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.text
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.code 32
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.type rem_4bit,%object
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.align 5
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rem_4bit:
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.short 0x0000,0x1C20,0x3840,0x2460
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.short 0x7080,0x6CA0,0x48C0,0x54E0
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.short 0xE100,0xFD20,0xD940,0xC560
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.short 0x9180,0x8DA0,0xA9C0,0xB5E0
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.size rem_4bit,.-rem_4bit
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.type rem_4bit_get,%function
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rem_4bit_get:
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sub $rem_4bit,pc,#8
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sub $rem_4bit,$rem_4bit,#32 @ &rem_4bit
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b .Lrem_4bit_got
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nop
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.size rem_4bit_get,.-rem_4bit_get
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.global gcm_ghash_4bit
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.type gcm_ghash_4bit,%function
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gcm_ghash_4bit:
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sub r12,pc,#8
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add $len,$inp,$len @ $len to point at the end
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stmdb sp!,{r3-r11,lr} @ save $len/end too
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sub r12,r12,#48 @ &rem_4bit
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ldmia r12,{r4-r11} @ copy rem_4bit ...
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stmdb sp!,{r4-r11} @ ... to stack
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ldrb $nlo,[$inp,#15]
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ldrb $nhi,[$Xi,#15]
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.Louter:
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eor $nlo,$nlo,$nhi
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and $nhi,$nlo,#0xf0
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and $nlo,$nlo,#0x0f
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mov $cnt,#14
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add $Zhh,$Htbl,$nlo,lsl#4
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ldmia $Zhh,{$Zll-$Zhh} @ load Htbl[nlo]
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ldrb $nlo,[$inp,#14]
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add $Thh,$Htbl,$nhi
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and $nhi,$Zll,#0xf @ rem
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ldmia $Thh,{$Tll-$Thh} @ load Htbl[nhi]
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mov $nhi,$nhi,lsl#1
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eor $Zll,$Tll,$Zll,lsr#4
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ldrh $Tll,[sp,$nhi] @ rem_4bit[rem]
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eor $Zll,$Zll,$Zlh,lsl#28
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ldrb $nhi,[$Xi,#14]
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eor $Zlh,$Tlh,$Zlh,lsr#4
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eor $Zlh,$Zlh,$Zhl,lsl#28
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eor $Zhl,$Thl,$Zhl,lsr#4
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eor $Zhl,$Zhl,$Zhh,lsl#28
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eor $Zhh,$Thh,$Zhh,lsr#4
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eor $nlo,$nlo,$nhi
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eor $Zhh,$Zhh,$Tll,lsl#16
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and $nhi,$nlo,#0xf0
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and $nlo,$nlo,#0x0f
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.Loop:
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add $Thh,$Htbl,$nlo,lsl#4
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subs $cnt,$cnt,#1
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ldmia $Thh,{$Tll-$Thh} @ load Htbl[nlo]
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and $nlo,$Zll,#0xf @ rem
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add $nlo,$nlo,$nlo
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eor $Zll,$Tll,$Zll,lsr#4
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ldrh $Tll,[sp,$nlo] @ rem_4bit[rem]
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eor $Zll,$Zll,$Zlh,lsl#28
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eor $Zlh,$Tlh,$Zlh,lsr#4
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eor $Zlh,$Zlh,$Zhl,lsl#28
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eor $Zhl,$Thl,$Zhl,lsr#4
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eor $Zhl,$Zhl,$Zhh,lsl#28
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eor $Zhh,$Thh,$Zhh,lsr#4
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ldrplb $nlo,[$inp,$cnt]
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add $Thh,$Htbl,$nhi
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eor $Zhh,$Zhh,$Tll,lsl#16 @ ^= rem_4bit[rem]
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ldmia $Thh,{$Tll-$Thh} @ load Htbl[nhi]
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and $nhi,$Zll,#0xf @ rem
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add $nhi,$nhi,$nhi
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eor $Zll,$Tll,$Zll,lsr#4
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ldrh $Tll,[sp,$nhi] @ rem_4bit[rem]
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eor $Zll,$Zll,$Zlh,lsl#28
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ldrplb $nhi,[$Xi,$cnt]
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eor $Zlh,$Tlh,$Zlh,lsr#4
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eor $Zlh,$Zlh,$Zhl,lsl#28
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eor $Zhl,$Thl,$Zhl,lsr#4
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eor $Zhl,$Zhl,$Zhh,lsl#28
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eor $Zhh,$Thh,$Zhh,lsr#4
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eorpl $nlo,$nlo,$nhi
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eor $Zhh,$Zhh,$Tll,lsl#16 @ ^= rem_4bit[rem]
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andpl $nhi,$nlo,#0xf0
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andpl $nlo,$nlo,#0x0f
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bpl .Loop
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ldr $len,[sp,#32] @ re-load $len/end
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add $inp,$inp,#16
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mov $nhi,$Zll
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___
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&Zsmash("cmp\t$inp,$len","ldrneb\t$nlo,[$inp,#15]");
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$code.=<<___;
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bne .Louter
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add sp,sp,#36
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ldmia sp!,{r4-r11,lr}
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tst lr,#1
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moveq pc,lr @ be binary compatible with V4, yet
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bx lr @ interoperable with Thumb ISA:-)
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.size gcm_ghash_4bit,.-gcm_ghash_4bit
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.global gcm_gmult_4bit
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.type gcm_gmult_4bit,%function
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gcm_gmult_4bit:
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stmdb sp!,{r4-r11,lr}
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ldrb $nlo,[$Xi,#15]
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b rem_4bit_get
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.Lrem_4bit_got:
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and $nhi,$nlo,#0xf0
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and $nlo,$nlo,#0x0f
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mov $cnt,#14
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add $Zhh,$Htbl,$nlo,lsl#4
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ldmia $Zhh,{$Zll-$Zhh} @ load Htbl[nlo]
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ldrb $nlo,[$Xi,#14]
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add $Thh,$Htbl,$nhi
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and $nhi,$Zll,#0xf @ rem
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ldmia $Thh,{$Tll-$Thh} @ load Htbl[nhi]
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mov $nhi,$nhi,lsl#1
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eor $Zll,$Tll,$Zll,lsr#4
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ldrh $Tll,[$rem_4bit,$nhi] @ rem_4bit[rem]
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eor $Zll,$Zll,$Zlh,lsl#28
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eor $Zlh,$Tlh,$Zlh,lsr#4
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eor $Zlh,$Zlh,$Zhl,lsl#28
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eor $Zhl,$Thl,$Zhl,lsr#4
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eor $Zhl,$Zhl,$Zhh,lsl#28
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eor $Zhh,$Thh,$Zhh,lsr#4
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and $nhi,$nlo,#0xf0
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eor $Zhh,$Zhh,$Tll,lsl#16
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and $nlo,$nlo,#0x0f
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.Loop2:
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add $Thh,$Htbl,$nlo,lsl#4
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subs $cnt,$cnt,#1
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ldmia $Thh,{$Tll-$Thh} @ load Htbl[nlo]
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and $nlo,$Zll,#0xf @ rem
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add $nlo,$nlo,$nlo
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eor $Zll,$Tll,$Zll,lsr#4
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ldrh $Tll,[$rem_4bit,$nlo] @ rem_4bit[rem]
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eor $Zll,$Zll,$Zlh,lsl#28
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eor $Zlh,$Tlh,$Zlh,lsr#4
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eor $Zlh,$Zlh,$Zhl,lsl#28
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eor $Zhl,$Thl,$Zhl,lsr#4
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eor $Zhl,$Zhl,$Zhh,lsl#28
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eor $Zhh,$Thh,$Zhh,lsr#4
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ldrplb $nlo,[$Xi,$cnt]
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add $Thh,$Htbl,$nhi
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eor $Zhh,$Zhh,$Tll,lsl#16 @ ^= rem_4bit[rem]
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ldmia $Thh,{$Tll-$Thh} @ load Htbl[nhi]
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and $nhi,$Zll,#0xf @ rem
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add $nhi,$nhi,$nhi
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eor $Zll,$Tll,$Zll,lsr#4
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ldrh $Tll,[$rem_4bit,$nhi] @ rem_4bit[rem]
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eor $Zll,$Zll,$Zlh,lsl#28
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eor $Zlh,$Tlh,$Zlh,lsr#4
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eor $Zlh,$Zlh,$Zhl,lsl#28
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eor $Zhl,$Thl,$Zhl,lsr#4
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eor $Zhl,$Zhl,$Zhh,lsl#28
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eor $Zhh,$Thh,$Zhh,lsr#4
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andpl $nhi,$nlo,#0xf0
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eor $Zhh,$Zhh,$Tll,lsl#16 @ ^= rem_4bit[rem]
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andpl $nlo,$nlo,#0x0f
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bpl .Loop2
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___
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&Zsmash();
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$code.=<<___;
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ldmia sp!,{r4-r11,lr}
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tst lr,#1
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moveq pc,lr @ be binary compatible with V4, yet
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bx lr @ interoperable with Thumb ISA:-)
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.size gcm_gmult_4bit,.-gcm_gmult_4bit
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.asciz "GHASH for ARMv4, CRYPTOGAMS by <appro\@openssl.org>"
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.align 2
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___
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$code =~ s/\`([^\`]*)\`/eval $1/gem;
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$code =~ s/\bbx\s+lr\b/.word\t0xe12fff1e/gm; # make it possible to compile with -march=armv4
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print $code;
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close STDOUT; # enforce flush
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