提交 e2f2a9af 编写于 作者: A Andy Polyakov

New scalable bn_mul_add_words loop, which provides up to >20% overall

performance improvement. Make module more gcc friendly and clarify
copyright issues for division routine.
上级 28a80034
.explicit
.text
.ident "ia64.S, Version 2.0"
.ident "ia64.S, Version 2.1"
.ident "IA-64 ISA artwork by Andy Polyakov <appro@fy.chalmers.se>"
//
......@@ -35,7 +35,7 @@
// What does it mean? You might ratiocinate that the original code
// should run just faster... Because sum of latencies is smaller...
// Wrong! Note that getf latency increased. This means that if a loop is
// scheduled for lower latency (and they are), then it will suffer from
// scheduled for lower latency (as they were), then it will suffer from
// stall condition and the code will therefore turn anti-scalable, e.g.
// original bn_mul_words spun at 5*n or 2.5 times slower than expected
// on Itanium2! What to do? Reschedule loops for Itanium2? But then
......@@ -145,6 +145,12 @@
// -Drum=nop.m in command line.
//
#if defined(_HPUX_SOURCE) && !defined(_LP64)
#define ADDP addp4
#else
#define ADDP add
#endif
#if 1
//
// bn_[add|sub]_words routines.
......@@ -178,27 +184,12 @@ bn_add_words:
brp.loop.imp .L_bn_add_words_ctop,.L_bn_add_words_cend-16
}
.body
{ .mib;
#if defined(_HPUX_SOURCE) && defined(_ILP32)
addp4 r14=0,r32 // rp
#else
mov r14=r32 // rp
#endif
{ .mib; ADDP r14=0,r32 // rp
mov r9=pr };;
{ .mii;
#if defined(_HPUX_SOURCE) && defined(_ILP32)
addp4 r15=0,r33 // ap
#else
mov r15=r33 // ap
#endif
{ .mii; ADDP r15=0,r33 // ap
mov ar.lc=r10
mov ar.ec=6 }
{ .mib;
#if defined(_HPUX_SOURCE) && defined(_ILP32)
addp4 r16=0,r34 // bp
#else
mov r16=r34 // bp
#endif
{ .mib; ADDP r16=0,r34 // bp
mov pr.rot=1<<16 };;
.L_bn_add_words_ctop:
......@@ -246,27 +237,12 @@ bn_sub_words:
brp.loop.imp .L_bn_sub_words_ctop,.L_bn_sub_words_cend-16
}
.body
{ .mib;
#if defined(_HPUX_SOURCE) && defined(_ILP32)
addp4 r14=0,r32 // rp
#else
mov r14=r32 // rp
#endif
{ .mib; ADDP r14=0,r32 // rp
mov r9=pr };;
{ .mii;
#if defined(_HPUX_SOURCE) && defined(_ILP32)
addp4 r15=0,r33 // ap
#else
mov r15=r33 // ap
#endif
{ .mii; ADDP r15=0,r33 // ap
mov ar.lc=r10
mov ar.ec=6 }
{ .mib;
#if defined(_HPUX_SOURCE) && defined(_ILP32)
addp4 r16=0,r34 // bp
#else
mov r16=r34 // bp
#endif
{ .mib; ADDP r16=0,r34 // bp
mov pr.rot=1<<16 };;
.L_bn_sub_words_ctop:
......@@ -332,16 +308,10 @@ bn_mul_words:
#ifndef XMA_TEMPTATION
{ .mii;
#if defined(_HPUX_SOURCE) && defined(_ILP32)
addp4 r14=0,r32 // rp
addp4 r15=0,r33 // ap
#else
mov r14=r32 // rp
mov r15=r33 // ap
#endif
{ .mmi; ADDP r14=0,r32 // rp
ADDP r15=0,r33 // ap
mov ar.lc=r10 }
{ .mii; mov r40=0 // serves as r35 at first (p27)
{ .mmi; mov r40=0 // serves as r35 at first (p27)
mov ar.ec=13 };;
// This loop spins in 2*(n+12) ticks. It's scheduled for data in Itanium
......@@ -424,89 +394,64 @@ bn_mul_words:
.global bn_mul_add_words#
.proc bn_mul_add_words#
.align 64
//.skip 0 // makes the loop split at 64-byte boundary
.skip 48 // makes the loop body aligned at 64-byte boundary
bn_mul_add_words:
.prologue
.fframe 0
.save ar.pfs,r2
{ .mii; alloc r2=ar.pfs,4,12,0,16
cmp4.le p6,p0=r34,r0 };;
{ .mfb; mov r8=r0 // return value
(p6) br.ret.spnt.many b0 };;
.save ar.lc,r3
{ .mii; sub r10=r34,r0,1
mov r3=ar.lc
mov r9=pr };;
.save pr,r9
{ .mmi; alloc r2=ar.pfs,4,4,0,8
cmp4.le p6,p0=r34,r0
mov r3=ar.lc };;
{ .mib; mov r8=r0 // return value
sub r10=r34,r0,1
(p6) br.ret.spnt.many b0 };;
.body
{ .mib; setf.sig f8=r35 // w
mov pr.rot=0x800001<<16
// ------^----- serves as (p50) at first (p27)
{ .mib; setf.sig f8=r35 // w
mov r9=pr
brp.loop.imp .L_bn_mul_add_words_ctop,.L_bn_mul_add_words_cend-16
}
{ .mii;
#if defined(_HPUX_SOURCE) && defined(_ILP32)
addp4 r14=0,r32 // rp
addp4 r15=0,r33 // ap
#else
mov r14=r32 // rp
mov r15=r33 // ap
#endif
{ .mmi; ADDP r14=0,r32 // rp
ADDP r15=0,r33 // ap
mov ar.lc=r10 }
{ .mii; mov r40=0 // serves as r35 at first (p27)
#if defined(_HPUX_SOURCE) && defined(_ILP32)
addp4 r18=0,r32 // rp copy
#else
mov r18=r32 // rp copy
#endif
mov ar.ec=15 };;
// This loop spins in 3*(n+14) ticks on Itanium and should spin in
// 2*(n+14) on "wider" IA-64 implementations (to be verified with new
// µ-architecture manuals as they become available). As usual it's
// possible to compress the epilogue, down to 10 in this case, at the
// cost of scalability. Compressed (and therefore non-scalable) loop
// running at 3*(n+11) would buy you ~10% on Itanium but take ~35%
// from "wider" IA-64 so let it be scalable! Special attention was
// paid for having the loop body split at 64-byte boundary. ld8 is
// scheduled for L1 cache as the data is more than likely there.
// Indeed, bn_mul_words has put it there a moment ago:-)
{ .mii; ADDP r16=0,r32 // rp copy
mov pr.rot=0x2001<<16
// ------^----- serves as (p40) at first (p27)
mov ar.ec=11 };;
// This loop spins in 3*(n+10) ticks on Itanium and in 2*(n+10) on
// Itanium 2. Yes, unlike previous versions it scales:-) Previous
// version was peforming *all* additions in IALU and was starving
// for those even on Itanium 2. In this version one addition is
// moved to FPU and is folded with multiplication. This is at cost
// of propogating the result from previous call to this subroutine
// to L2 cache... In other words negligible even for shorter keys.
// *Overall* performance improvement [over previous version] varies
// from 11 to 22 percent depending on key length.
.L_bn_mul_add_words_ctop:
{ .mfi; (p25) getf.sig r36=f52 // low
(p21) xmpy.lu f48=f37,f8
(p28) cmp.ltu p54,p50=r41,r39 }
{ .mfi; (p16) ldf8 f32=[r15],8
(p21) xmpy.hu f40=f37,f8
(p28) add r45=r45,r41 };;
{ .mii; (p25) getf.sig r32=f44 // high
.pred.rel "mutex",p50,p54
(p50) add r40=r38,r35 // (p27)
(p54) add r40=r38,r35,1 } // (p27)
{ .mfb; (p28) cmp.ltu.unc p60,p0=r45,r41
(p0) nop.f 0x0
(p0) nop.b 0x0 }
{ .mii; (p27) ld8 r44=[r18],8
(p62) cmp.eq.or p61,p0=-1,r46
(p62) add r46=1,r46 }
{ .mfb; (p30) st8 [r14]=r47,8
(p0) nop.f 0x0
.pred.rel "mutex",p40,p42
{ .mfi; (p23) getf.sig r36=f45 // low
(p20) xma.lu f42=f36,f8,f50 // low
(p40) add r39=r39,r35 } // (p27)
{ .mfi; (p16) ldf8 f32=[r15],8 // *(ap++)
(p20) xma.hu f36=f36,f8,f50 // high
(p42) add r39=r39,r35,1 };; // (p27)
{ .mmi; (p24) getf.sig r32=f40 // high
(p16) ldf8 f46=[r16],8 // *(rp1++)
(p40) cmp.ltu p41,p39=r39,r35 } // (p27)
{ .mib; (p26) st8 [r14]=r39,8 // *(rp2++)
(p42) cmp.leu p41,p39=r39,r35 // (p27)
br.ctop.sptk .L_bn_mul_add_words_ctop};;
.L_bn_mul_add_words_cend:
{ .mii; nop.m 0x0
.pred.rel "mutex",p53,p57
(p53) add r8=r38,r0
(p57) add r8=r38,r0,1 }
{ .mfb; nop.m 0x0
nop.f 0x0
nop.b 0x0 };;
{ .mii;
(p63) add r8=1,r8
mov pr=r9,0x1ffff
mov ar.lc=r3 }
{ .mfb; rum 1<<5 // clear um.mfh
nop.f 0x0
{ .mmi; .pred.rel "mutex",p40,p42
(p40) add r8=r35,r0
(p42) add r8=r35,r0,1
mov pr=r9,0x1ffff }
{ .mib; rum 1<<5 // clear um.mfh
mov ar.lc=r3
br.ret.sptk.many b0 };;
.endp bn_mul_add_words#
#endif
......@@ -527,7 +472,8 @@ bn_sqr_words:
sxt4 r34=r34 };;
{ .mii; cmp.le p6,p0=r34,r0
mov r8=r0 } // return value
{ .mfb; nop.f 0x0
{ .mfb; ADDP r32=0,r32
nop.f 0x0
(p6) br.ret.spnt.many b0 };;
.save ar.lc,r3
......@@ -536,11 +482,7 @@ bn_sqr_words:
mov r9=pr };;
.body
#if defined(_HPUX_SOURCE) && defined(_ILP32)
{ .mii; addp4 r32=0,r32
addp4 r33=0,r33 };;
#endif
{ .mib;
{ .mib; ADDP r33=0,r33
mov pr.rot=1<<16
brp.loop.imp .L_bn_sqr_words_ctop,.L_bn_sqr_words_cend-16
}
......@@ -605,7 +547,7 @@ bn_sqr_comba8:
.prologue
.fframe 0
.save ar.pfs,r2
#if defined(_HPUX_SOURCE) && defined(_ILP32)
#if defined(_HPUX_SOURCE) && !defined(_LP64)
{ .mii; alloc r2=ar.pfs,2,1,0,0
addp4 r33=0,r33
addp4 r32=0,r32 };;
......@@ -631,6 +573,10 @@ bn_sqr_comba8:
// clause in Itanium µ-architecture manual? Comments are welcomed and
// highly appreciated.
//
// On Itanium 2 it takes ~190 ticks. This is because of stalls on
// result from getf.sig. I do nothing about it at this point for
// reasons depicted below.
//
// However! It should be noted that even 160 ticks is darn good result
// as it's over 10 (yes, ten, spelled as t-e-n) times faster than the
// C version (compiled with gcc with inline assembler). I really
......@@ -673,7 +619,7 @@ bn_mul_comba8:
.prologue
.fframe 0
.save ar.pfs,r2
#if defined(_HPUX_SOURCE) && defined(_ILP32)
#if defined(_HPUX_SOURCE) && !defined(_LP64)
{ .mii; alloc r2=ar.pfs,3,0,0,0
addp4 r33=0,r33
addp4 r34=0,r34 };;
......@@ -1231,7 +1177,7 @@ bn_sqr_comba4:
.prologue
.fframe 0
.save ar.pfs,r2
#if defined(_HPUX_SOURCE) && defined(_ILP32)
#if defined(_HPUX_SOURCE) && !defined(_LP64)
{ .mii; alloc r2=ar.pfs,2,1,0,0
addp4 r32=0,r32
addp4 r33=0,r33 };;
......@@ -1264,7 +1210,7 @@ bn_mul_comba4:
.prologue
.fframe 0
.save ar.pfs,r2
#if defined(_HPUX_SOURCE) && defined(_ILP32)
#if defined(_HPUX_SOURCE) && !defined(_LP64)
{ .mii; alloc r2=ar.pfs,3,0,0,0
addp4 r33=0,r33
addp4 r34=0,r34 };;
......@@ -1448,8 +1394,8 @@ bn_mul_comba4:
#define I r21
#if 0
// Some preprocessors (most notably HP-UX) apper to be allergic to
// macros enclosed to parenthesis as these three will be.
// Some preprocessors (most notably HP-UX) appear to be allergic to
// macros enclosed to parenthesis [as these three were].
#define cont p16
#define break p0 // p20
#define equ p24
......@@ -1581,9 +1527,18 @@ bn_div_words:
// output: f8 = (int)(a/b)
// clobbered: f8,f9,f10,f11,pred
pred=p15
// This procedure is essentially Intel code and therefore is
// copyrighted to Intel Corporation (I suppose...). It's sligtly
// modified for specific needs.
// One can argue that this snippet is copyrighted to Intel
// Corporation, as it's essentially identical to one of those
// found in "Divide, Square Root and Remainder" section at
// http://www.intel.com/software/products/opensource/libraries/num.htm.
// Yes, I admit that the referred code was used as template,
// but after I realized that there hardly is any other instruction
// sequence which would perform this operation. I mean I figure that
// any independent attempt to implement high-performance division
// will result in code virtually identical to the Intel code. It
// should be noted though that below division kernel is 1 cycle
// faster than Intel one (note commented splits:-), not to mention
// original prologue (rather lack of one) and epilogue.
.align 32
.skip 16
.L_udiv64_32_b6:
......
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