/* Apple Copyright 2009
CoreOS - vector & Numerics, cclee 10-22-09
This following source code implements a vectorized version of adler32 computation that is defined in zlib.
The target architectures are x86_64 and i386.
Given 2 unsigned 32-bit alder and sum2 (both pre-modulo by BASE=65521) and a sequence of input bytes x[0],...x[N-1].
The adler-sum2 pair is updated according to
for (i=0 sum2 = (sum2+adler)%BASE
To reduce/save the modulo operations, it can be shown that, if initial alder and sum2 are less than BASE(=65521),
adler and sum2 (in 32-bit representation), will never overflow for the next NMAX=5552 bytes. This simplifies the
algorithm to
for (i=0 adler+=x[i+k];
sum2+=adler;
}
adler%=BASE;
sum2%=BASE;
}
The hand optimization of this function is now reduced to
for (k=0 sum2+=adler;
}
This subtask turns out to be very vecterizable. Suppose we perform the adler/sum2 update once per K bytes,
for (k=0 sum2+=adler;
}
It can be shown that the sum2-adler pair can be updated according to
sum2 += adler*K sum2 += (x[0]*K + x[1]*(K-1) + ... + x[K-1]*1) The last 2 equations obviously show that the adler-sum2 pair update can be speeded up using vector processor.
The input vector [ x[0] x[1] ... x[K-1] ]. And we need two coefficient vectors
[ 1 1 1 ... 1 ] for adler update.
[ K K-1 ... 1 ] for sum2 update.
The implementation below reads vector (K=16,32,48,64) into xmm registers, and sets up coefficient vectors in xmm
registers. It then uses SSE instructions to perform the aforementioned vector computation.
For i386, NMAX/16 = 347, whenever possible (NMAX-bytes block), it calls 173 times of macro code DO32 (K=32),
followed by a single DO16 (K=16), before calling a modulo operation for adler and sum2.
For x86_64 (where more xmm registers are available), NMAX/64 = 86, whenever possible (NMAX-bytes block),
it calls 86 times of macro code DO64 (K=64), followed by a single DO48 (K=48),
before calling a modulo operation for adler and sum2.
*/
/* added cpu_capability to detect kHasSupplementalSSE3 to branch into code w or wo SupplementalSSE3
Previously, ssse3 code was intentionally turned off, because Yonah does not support ssse3
add code here to probe cpu_capabilities for ssse3 support
if ssse3 is supported, branch to ssse3-based code, otherwise use the original code
cclee 5-3-10
*/
#define BASE 65521 /* largest prime smaller than 65536 */
#define NMAX 5552 /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
// uLong adler32_vec(unsigned int adler, unsigned int sum2, const Bytef *buf, int len) {
// unsigned n// len -= NMAX// do {
// DO16(buf)// } while (--n)// MOD(sum2)// if (len) { /* avoid modulos if none remaining */
// while (len >= 16) {
// len -= 16// buf += 16// while (len--) {
// adler += *buf++// }
// MOD(adler)// }
// return adler | (sum2 << 16)
#if (defined __i386__ || defined __x86_64__)
#include <i386/cpu_capabilities.h>
.text
.align 4,0x90
.globl _adler32_vec
_adler32_vec:
#if (defined __i386__)
pushl %ebp
movl %esp, %ebp
pushl %ebx
pushl %edi
pushl %esi
#ifdef KERNEL // if this is for kernel, need to save xmm registers
subl $140, %esp // to save %xmm0-%xmm7 into stack, extra 12 to align %esp to 16-byte boundary
movaps %xmm0, 0(%esp) // save xmm0, offset -12 for ebx/edi/esi
movaps %xmm1, 16(%esp) // save xmm1
movaps %xmm2, 32(%esp) // save xmm2
movaps %xmm3, 48(%esp) // save xmm3
movaps %xmm4, 64(%esp) // save xmm4
movaps %xmm5, 80(%esp) // save xmm5
movaps %xmm6, 96(%esp) // save xmm6
movaps %xmm7, 112(%esp) // save xmm7, if this is for SSSE3 or above
#endif
#define adler %edi // 8(%ebp)
#define sum2 %esi // 12(%ebp)
#define buf %ecx // 16(%ebp)
#define len %ebx // 20(%ebp)
#define zero %xmm0
#define ones %xmm5
movl 8(%ebp), adler
movl 12(%ebp), sum2
movl 16(%ebp), buf // use ecx as buf pointer
movl 20(%ebp), len
.macro modulo_BASE
movl $$-2146992015, %eax // 1/BASE in Q47
mull adler // edx:eax = adler divided by BASE in Q47
shrl $$15, %edx // edx is now the floor integer of adler and BASE
imull $$BASE, %edx, %edx // edx * BASE
subl %edx, adler // adler -= edx*BASE
movl $$-2146992015, %eax // 1/BASE in Q47
mull sum2 // edx:eax = sum2 divided by BASE in Q47
shrl $$15, %edx // edx is now the floor integer of sum2 and BASE
imull $$BASE, %edx, %eax // eax = edx * BASE
subl %eax, sum2 // sum2 -= sdx*BASE
.endmacro
// update adler/sum2 according to a new 16-byte vector
.macro DO16
movaps (buf), %xmm1 // 16 bytes vector, in xmm1
movaps %xmm1, %xmm3 // a copy of the vector, used for unsigned byte in the destination of pmaddubsw
addl $$16, buf // buf -> next vector
psadbw zero, %xmm1 // 2 16-bit words to be added for adler in xmm1
pmaddubsw %xmm4, %xmm3 // 8 16-bit words to be added for sum2 in xmm3
imull $$16, adler, %edx // edx = 16*adler pmaddwd ones, %xmm3 // 4 32-bit elements to be added for sum2 in xmm3
paddq %xmm2, %xmm1 // xmm1 lower 32-bit to be added to adler
addl %edx, sum2 // sum2 += adler*16 movd %xmm1, %edx // to be added to adler
paddd %xmm2, %xmm3 // 2 32-bits elements in xmm3 to be added to sum2
addl %edx, adler // update adler
movd %xmm3, %edx // to be added to sum2
psrlq $$32, %xmm3 // another 32-bit to be added to sum2
addl %edx, sum2 // sum2 += 1st half of update
movd %xmm3, %edx // to be added to sum2
addl %edx, sum2 // sum2 += 2nd half of update
.endm
// update adler/sum2 according to a new 32-byte vector
.macro DO32
imull $$32, adler, %edx // edx = 32*adler
movaps (buf), %xmm1 // 1st 16 bytes vector
movaps 16(buf), %xmm7 // 2nd 16 bytes vector
movaps %xmm1, %xmm3 // a copy of 1st vector, used for unsigned byte in the destination of pmaddubsw
movaps %xmm7, %xmm2 // a copy of 2nd vector, used for unsigned byte in the destination of pmaddubsw
psadbw zero, %xmm1 // 2 16-bit words to be added for adler in xmm1
psadbw zero, %xmm7 // 2 16-bit words to be added for adler in xmm7
addl %edx, sum2 // sum2 += adler*32 pmaddubsw %xmm4, %xmm2 // 8 16-bit words to be added for sum2 in xmm2
paddd %xmm7, %xmm1 // 2 16-bit words to be added for adler in xmm1
paddd %xmm2, %xmm3 // 8 16-bit words to be added for sum2 in xmm3
addl $$32, buf // buf -> vector for next iteration
movhlps %xmm1, %xmm2 // higher 16-bit word (for adler) in xmm2
pmaddwd ones, %xmm3 // 4 32-bit elements to be added for sum2 in xmm3
paddq %xmm2, %xmm1 // xmm1 lower 32-bit to be added to adler
movhlps %xmm3, %xmm2 // 2 higher 32-bit elements of xmm3 to be added to lower 2 32-bit elements
movd %xmm1, %edx // to be added to adler
paddd %xmm2, %xmm3 // 2 32-bits elements in xmm3 to be added to sum2
addl %edx, adler // update adler
movd %xmm3, %edx // to be added to sum2
psrlq $$32, %xmm3 // another 32-bit to be added to sum2
addl %edx, sum2 // sum2 += 1st half of update
movd %xmm3, %edx // to be added to sum2
addl %edx, sum2 // sum2 += 2nd half of update
.endm
// this defines the macro DO16 for SSSE3 not supported
.macro DO16_nossse3
movaps (buf), %xmm1 // 16 bytes vector
movaps %xmm1, %xmm3 // a copy of the vector, the lower 8 bytes to be shuffled into 8 words
movaps %xmm1, %xmm2 // a copy of the vector, the higher 8 bytes to be shuffled into 8 words
psrldq $$8, %xmm2 // shift down 8 bytes, to reuse the shuffle vector
punpcklbw zero, %xmm3 // convert lower 8 bytes into 8 words
punpcklbw zero, %xmm2 // convert higher 8 bytes into 8 words
pmullw %xmm6, %xmm3 // lower 8 words * 16:9
pmullw %xmm4, %xmm2 // higher 8 words * 8:1
addl $$16, buf // buf -> next vector
psadbw zero, %xmm1 // 2 16-bit words to be added for adler in xmm1
paddw %xmm2, %xmm3 // 8 16-bit words to be added for sum2 in xmm3
imull $$16, adler, %edx // edx = 16*adler pmaddwd ones, %xmm3 // 4 32-bit elements to be added for sum2 in xmm3
paddq %xmm2, %xmm1 // xmm1 lower 32-bit to be added to adler
addl %edx, sum2 // sum2 += adler*16 movd %xmm1, %edx // to be added to adler
paddd %xmm2, %xmm3 // 2 32-bits elements in xmm3 to be added to sum2
addl %edx, adler // update adler
movd %xmm3, %edx // to be added to sum2
psrlq $$32, %xmm3 // another 32-bit to be added to sum2
addl %edx, sum2 // sum2 += 1st half of update
movd %xmm3, %edx // to be added to sum2
addl %edx, sum2 // sum2 += 2nd half of update
.endm
#ifdef KERNEL
leal __cpu_capabilities, %eax // %eax -> __cpu_capabilities
mov (%eax), %eax // %eax = __cpu_capabilities
#else
mov _COMM_PAGE_CPU_CAPABILITIES, %eax
#endif
test $(kHasSupplementalSSE3), %eax // __cpu_capabilities & kHasAES
je L_no_ssse3
// i386 adler32 with ssse3
// need to fill up xmm4/xmm5/xmm6 only if len>=16
cmpl $16, len
jl L_skip_loading_tables
// set up table starting address to %eax
leal sum2_coefficients, %eax
// reading coefficients
pxor zero, zero
movaps (%eax), %xmm6 // coefficients for computing sum2 : pmaddubsw 32:17
movaps 16(%eax), %xmm4 // coefficients for computing sum2 : pmaddubsw 16:1
movaps 32(%eax), ones // coefficients for computing sum2 : pmaddwd 1,1,...,1
L_skip_loading_tables:
cmpl $NMAX, len // len vs NMAX
jl len_lessthan_NMAX // if (len < NMAX), skip the following NMAX batches processing
len_ge_NMAX_loop: // while (len>=NMAX) {
subl $NMAX, len // len -= NMAX
movl $(NMAX/32), %eax // n = NMAX/32
n_loop: // do {
DO32 // update adler/sum2 for a 32-byte input
decl %eax // n-- DO16 // update adler/sum2 for a 16-byte input
modulo_BASE // (adler/sum2) modulo BASE jge len_ge_NMAX_loop // } /* len>=NMAX */
len_lessthan_NMAX:
subl $32, len // pre-decrement len by 32
jl len_lessthan_32 // if len < 32, skip the 32-vector code
len32_loop: // while (len>=32) {
DO32 // update adler/sum2 for a 32-byte input
subl $32, len // len -= 32
len_lessthan_32:
addl $(32-16), len // post-increment by 32 + pre-decrement by 16 on len
jl L_len_lessthan_16 // if len < 16, skip the 16-vector code
DO16 // update adler/sum2 for a 16-byte input
subl $16, len // len -= 16L_len_lessthan_16:
addl $16, len // post-increment len by 16
jz len_is_zero // if len==0, branch over scalar processing
0: // while (len) {
movzbl (buf), %edx // new input byte
incl buf // buf++
addl %edx, adler // adler += *buf
addl adler, sum2 // sum2 += adler
subl $1, len // len--
jg 0b // }
len_is_zero:
modulo_BASE // (adler/sum2) modulo BASE // construct 32-bit (sum2<<16 | adler) to be returned
sall $16, sum2 // sum2 <<16
movl adler, %eax // adler
orl sum2, %eax // sum2<<16 | adler
#ifdef KERNEL // if this is for kernel code, need to restore xmm registers
movaps (%esp), %xmm0 // restore xmm0, offset -12 for ebx/edi/esi
movaps 16(%esp), %xmm1 // restore xmm1
movaps 32(%esp), %xmm2 // restore xmm2
movaps 48(%esp), %xmm3 // restore xmm3
movaps 64(%esp), %xmm4 // restore xmm4
movaps 80(%esp), %xmm5 // restore xmm5
movaps 96(%esp), %xmm6 // restore xmm6
movaps 112(%esp), %xmm7 // restore xmm7, if this is for SSSE3 or above
addl $140, %esp // we've already restored %xmm0-%xmm7 from stack
#endif
popl %esi
popl %edi
popl %ebx
leave // pop ebp out from stack
ret
L_no_ssse3:
// i386 adler32 without ssse3
// need to fill up xmm4/xmm5/xmm6 only if len>=16
cmpl $16, len
jl 2f
// set up table starting address to %eax
leal sum2_coefficients, %eax
// reading coefficients
pxor zero, zero
movaps 48(%eax), %xmm6 // coefficients for computing sum2 : pmaddubsw 16:9
movaps 64(%eax), %xmm4 // coefficients for computing sum2 : pmaddubsw 8:1
movaps 80(%eax), ones // coefficients for computing sum2 : pmaddwd 1,1,...,1
2:
cmpl $NMAX, len // len vs NMAX
jl 3f // if (len < NMAX), skip the following NMAX batches processing
0: // while (len>=NMAX) {
subl $NMAX, len // len -= NMAX
movl $(NMAX/16), %eax // n = NMAX/16
1: // do {
DO16_nossse3 // update adler/sum2 for a 16-byte input
decl %eax // n--
modulo_BASE // (adler/sum2) modulo BASE cmpl $NMAX, len //
jge 0b // } /* len>=NMAX */
3:
subl $16, len // pre-decrement len by 16
jl L_len_lessthan_16 // if len < 16, skip the 16-vector code
DO16_nossse3 // update adler/sum2 for a 16-byte input
subl $16, len // len -= 16
.const
.align 4
sum2_coefficients: // used for vectorizing adler32 computation
.byte 32
.byte 31
.byte 30
.byte 29
.byte 28
.byte 27
.byte 26
.byte 25
.byte 24
.byte 23
.byte 22
.byte 21
.byte 20
.byte 19
.byte 18
.byte 17
.byte 16
.byte 15
.byte 14
.byte 13
.byte 12
.byte 11
.byte 10
.byte 9
.byte 8
.byte 7
.byte 6
.byte 5
.byte 4
.byte 3
.byte 2
.byte 1
// coefficients for pmaddwd, to combine into 4 32-bit elements for sum2
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
// data for without ssse3
.word 16
.word 15
.word 14
.word 13
.word 12
.word 11
.word 10
.word 9
.word 8
.word 7
.word 6
.word 5
.word 4
.word 3
.word 2
.word 1
// coefficients for pmaddwd, to combine into 4 32-bit elements for sum2
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
#else // (defined __x86_64__)
movq __cpu_capabilities@GOTPCREL(%rip), %rax // %rax -> __cpu_capabilities
mov (%rax), %eax // %eax = __cpu_capabilities
test $(kHasSupplementalSSE3), %eax // __cpu_capabilities & kHasSupplementalSSE3
jne L_has_ssse3
// ----------------------------------------------------------------------------------
// the following is added for x86_64 without SSSE3 support
// it is essentially a translated copy of the i386 code without SSSE3 code
// ----------------------------------------------------------------------------------
// input :
// adler : rdi
// sum2 : rsi
// buf : rdx
// len : rcx
pushq %rbp
movq %rsp, %rbp
pushq %rbx
#ifdef KERNEL // if for kernel, save %xmm0-%xmm11
subq $200, %rsp // allocate for %xmm0-%xmm11 (192 bytes), extra 8 to align %rsp to 16-byte boundary
movaps %xmm0, -32(%rbp)
movaps %xmm1, -48(%rbp)
movaps %xmm2, -64(%rbp)
movaps %xmm3, -80(%rbp)
movaps %xmm4, -96(%rbp)
movaps %xmm5, -112(%rbp)
movaps %xmm6, -128(%rbp)
#endif
#define adler %rdi // 16(%rbp)
#define sum2 %rsi // 24(%ebp)
#define buf %rcx // 32(%ebp)
#define len %rbx // 40(%ebp)
#define zero %xmm0
#define ones %xmm5
movq %rcx, len
movq %rdx, buf
.macro modulo_BASE
movl $$-2146992015, %eax // 1/BASE in Q47
mull %edi // edx:eax = adler divided by BASE in Q47
shrl $$15, %edx // edx is now the floor integer of adler and BASE
imull $$BASE, %edx, %edx // edx * BASE
subq %rdx, adler // adler -= edx*BASE
movl $$-2146992015, %eax // 1/BASE in Q47
mull %esi // edx:eax = sum2 divided by BASE in Q47
shrl $$15, %edx // edx is now the floor integer of sum2 and BASE
imull $$BASE, %edx, %eax // eax = edx * BASE
subq %rax, sum2 // sum2 -= sdx*BASE
.endmacro
// update adler/sum2 according to a new 16-byte vector, no ssse3
.macro DO16_nossse3
movaps (buf), %xmm1 // 16 bytes vector
movaps %xmm1, %xmm3 // a copy of the vector, the lower 8 bytes to be shuffled into 8 words
movaps %xmm1, %xmm2 // a copy of the vector, the higher 8 bytes to be shuffled into 8 words
psrldq $$8, %xmm2 // shift down 8 bytes, to reuse the shuffle vector
punpcklbw zero, %xmm3 // convert lower 8 bytes into 8 words
punpcklbw zero, %xmm2 // convert higher 8 bytes into 8 words
pmullw %xmm6, %xmm3 // lower 8 words * 16:9
pmullw %xmm4, %xmm2 // higher 8 words * 8:1
add $$16, buf // buf -> next vector
psadbw zero, %xmm1 // 2 16-bit words to be added for adler in xmm1
paddw %xmm2, %xmm3 // 8 16-bit words to be added for sum2 in xmm3
imulq $$16, adler, %rdx // edx = 16*adler pmaddwd ones, %xmm3 // 4 32-bit elements to be added for sum2 in xmm3
paddq %xmm2, %xmm1 // xmm1 lower 32-bit to be added to adler
add %rdx, sum2 // sum2 += adler*16 movd %xmm1, %edx // to be added to adler
paddd %xmm2, %xmm3 // 2 32-bits elements in xmm3 to be added to sum2
addq %rdx, adler // update adler
movd %xmm3, %edx // to be added to sum2
psrlq $$32, %xmm3 // another 32-bit to be added to sum2
addq %rdx, sum2 // sum2 += 1st half of update
movd %xmm3, %edx // to be added to sum2
addq %rdx, sum2 // sum2 += 2nd half of update
.endm
// need to fill up xmm4/xmm5/xmm6 only if len>=16
cmpq $16, len
jl 0f
// set up table starting address to %eax
leaq sum2_coefficients_nossse3(%rip), %rax
// reading coefficients
pxor zero, zero
movaps (%rax), %xmm6 // coefficients for computing sum2 : pmaddubsw 16:9
movaps 16(%rax), %xmm4 // coefficients for computing sum2 : pmaddubsw 8:1
movaps 32(%rax), ones // coefficients for computing sum2 : pmaddwd 1,1,...,1
0:
cmp $NMAX, len // len vs NMAX
jl 3f // if (len < NMAX), skip the following NMAX batches processing
0: // while (len>=NMAX) {
sub $NMAX, len // len -= NMAX
mov $(NMAX/16), %eax // n = NMAX/16
1: // do {
DO16_nossse3 // update adler/sum2 for a 16-byte input
decl %eax // n--
modulo_BASE // (adler/sum2) modulo BASE cmp $NMAX, len //
jge 0b // } /* len>=NMAX */
3:
sub $16, len // pre-decrement len by 16
jl 2f // if len < 16, skip the 16-vector code
DO16_nossse3 // update adler/sum2 for a 16-byte input
sub $16, len // len -= 162:
add $16, len // post-increment len by 16
jz 1f // if len==0, branch over scalar processing
0: // while (len) {
movzbq (buf), %rdx // new input byte
incq buf // buf++
addq %rdx, adler // adler += *buf
addq adler, sum2 // sum2 += adler
decq len // len--
jg 0b // }
1:
modulo_BASE // (adler/sum2) modulo BASE // construct 32-bit (sum2<<16 | adler) to be returned
salq $16, sum2 // sum2 <<16
movq adler, %rax // adler
orq sum2, %rax // sum2<<16 | adler
#ifdef KERNEL // if this is for kernel code, need to restore xmm registers
movaps -32(%rbp), %xmm0
movaps -48(%rbp), %xmm1
movaps -64(%rbp), %xmm2
movaps -80(%rbp), %xmm3
movaps -96(%rbp), %xmm4
movaps -112(%rbp), %xmm5
movaps -128(%rbp), %xmm6
addq $200, %rsp // we've already restored %xmm0-%xmm11 from stack
#endif
popq %rbx
leave
ret
.const
.align 4
sum2_coefficients_nossse3: // used for vectorizing adler32 computation
// data for without ssse3
.word 16
.word 15
.word 14
.word 13
.word 12
.word 11
.word 10
.word 9
.word 8
.word 7
.word 6
.word 5
.word 4
.word 3
.word 2
.word 1
// coefficients for pmaddwd, to combine into 4 32-bit elements for sum2
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
.text
// ----------------------------------------------------------------------------------
// the following is the original x86_64 adler32_vec code that uses SSSE3 instructions
// ----------------------------------------------------------------------------------
L_has_ssse3:
// input :
// adler : rdi
// sum2 : rsi
// buf : rdx
// len : rcx
pushq %rbp
movq %rsp, %rbp
pushq %rbx
#ifdef KERNEL // if for kernel, save %xmm0-%xmm11
subq $200, %rsp // allocate for %xmm0-%xmm11 (192 bytes), extra 8 to align %rsp to 16-byte boundary
movaps %xmm0, -32(%rbp)
movaps %xmm1, -48(%rbp)
movaps %xmm2, -64(%rbp)
movaps %xmm3, -80(%rbp)
movaps %xmm4, -96(%rbp)
movaps %xmm5, -112(%rbp)
movaps %xmm6, -128(%rbp)
movaps %xmm7, -144(%rbp)
movaps %xmm8, -160(%rbp)
movaps %xmm9, -176(%rbp)
movaps %xmm10, -192(%rbp)
movaps %xmm11, -208(%rbp)
#endif
#define adler %rdi // 16(%rbp)
#define sum2 %rsi // 24(%ebp)
#define buf %rcx // 32(%ebp)
#define len %rbx // 40(%ebp)
#define zero %xmm0
#define ones %xmm5
movq %rcx, len
movq %rdx, buf
// update adler/sum2 according to a new 16-byte vector
.macro DO16
movaps (buf), %xmm1 // 16 bytes vector
movaps %xmm1, %xmm3 // a copy of the vector, used for unsigned byte in the destination of pmaddubsw
addq $$16, buf // buf -> next vector
psadbw zero, %xmm1 // 2 16-bit words to be added for adler in xmm1
pmaddubsw %xmm4, %xmm3 // 8 16-bit words to be added for sum2 in xmm3
imulq $$16, adler, %rdx // edx = 16*adler pmaddwd ones, %xmm3 // 4 32-bit elements to be added for sum2 in xmm3
paddq %xmm2, %xmm1 // xmm1 lower 32-bit to be added to adler
addq %rdx, sum2 // sum2 += adler*16 movd %xmm1, %edx // to be added to adler
paddd %xmm2, %xmm3 // 2 32-bits elements in xmm3 to be added to sum2
addq %rdx, adler // update adler
movd %xmm3, %edx // to be added to sum2
psrlq $$32, %xmm3 // another 32-bit to be added to sum2
addq %rdx, sum2 // sum2 += 1st half of update
movd %xmm3, %edx // to be added to sum2
addq %rdx, sum2 // sum2 += 2nd half of update
.endm
// update adler/sum2 according to a new 32-byte vector
.macro DO32
imulq $$32, adler, %rdx // edx = 32*adler
movaps (buf), %xmm1 // 1st 16 bytes vector
movaps 16(buf), %xmm7 // 2nd 16 bytes vector
movaps %xmm1, %xmm3 // a copy of 1st vector, used for unsigned byte in the destination of pmaddubsw
movaps %xmm7, %xmm2 // a copy of 2nd vector, used for unsigned byte in the destination of pmaddubsw
psadbw zero, %xmm1 // 2 16-bit words to be added for adler in xmm1
psadbw zero, %xmm7 // 2 16-bit words to be added for adler in xmm7
addq %rdx, sum2 // sum2 += adler*32 pmaddubsw %xmm4, %xmm2 // 8 16-bit words to be added for sum2 in xmm2
paddd %xmm7, %xmm1 // 2 16-bit words to be added for adler in xmm1
paddw %xmm2, %xmm3 // 8 16-bit words to be added for sum2 in xmm3
addq $$32, buf // buf -> vector for next iteration
movhlps %xmm1, %xmm2 // higher 16-bit word (for adler) in xmm2
pmaddwd ones, %xmm3 // 4 32-bit elements to be added for sum2 in xmm3
paddq %xmm2, %xmm1 // xmm1 lower 32-bit to be added to adler
movhlps %xmm3, %xmm2 // 2 higher 32-bit elements of xmm3 to be added to lower 2 32-bit elements
movd %xmm1, %edx // to be added to adler
paddd %xmm2, %xmm3 // 2 32-bits elements in xmm3 to be added to sum2
addq %rdx, adler // update adler
movd %xmm3, %edx // to be added to sum2
psrlq $$32, %xmm3 // another 32-bit to be added to sum2
addq %rdx, sum2 // sum2 += 1st half of update
movd %xmm3, %edx // to be added to sum2
addq %rdx, sum2 // sum2 += 2nd half of update
.endm
// update adler/sum2 according to a new 48-byte vector
.macro DO48
imulq $$48, adler, %rdx // edx = 48*adler
movaps (buf), %xmm7 // 1st 16 bytes vector
movaps 16(buf), %xmm10 // 2nd 16 bytes vector
movaps 32(buf), %xmm11 // 3rd 16 bytes vector
movaps %xmm7, %xmm1 // 1st vector
movaps %xmm10, %xmm2 // 2nd vector
movaps %xmm11, %xmm3 // 3rd vector
psadbw zero, %xmm7 // 1st vector for adler
psadbw zero, %xmm10 // 2nd vector for adler
psadbw zero, %xmm11 // 3rd vector for adler
addq %rdx, sum2 // sum2 += adler*48 pmaddubsw %xmm9, %xmm1 // 8 16-bit words to be added for sum2 : 1st vector
pmaddubsw %xmm6, %xmm2 // 8 16-bit words to be added for sum2 : 2nd vector
pmaddubsw %xmm4, %xmm3 // 8 16-bit words to be added for sum2 : 3rd vector
pmaddwd ones, %xmm1 // 4 32-bit elements to be added for sum2 in xmm1
pmaddwd ones, %xmm2 // 4 32-bit elements to be added for sum2 in xmm2
pmaddwd ones, %xmm3 // 4 32-bit elements to be added for sum2 in xmm3
paddd %xmm10, %xmm7 // 2 16-bit words to be added for adler
paddd %xmm11, %xmm7 // 2 16-bit words to be added for adler
paddd %xmm1, %xmm3 // 4 32-bit elements to be added for sum2
paddd %xmm2, %xmm3 // 4 32-bit elements to be added for sum2
addq $$48, buf // buf -> vector for next iteration
movhlps %xmm7, %xmm2 // higher 16-bit word (for adler) in xmm2
paddq %xmm2, %xmm7 // xmm7 lower 32-bit to be added to adler
movhlps %xmm3, %xmm2 // 2 higher 32-bit elements of xmm3 to be added to lower 2 32-bit elements
movd %xmm7, %edx // to be added to adler
paddd %xmm2, %xmm3 // 2 32-bits elements in xmm3 to be added to sum2
addq %rdx, adler // update adler
movd %xmm3, %edx // to be added to sum2
psrlq $$32, %xmm3 // another 32-bit to be added to sum2
addq %rdx, sum2 // sum2 += 1st half of update
movd %xmm3, %edx // to be added to sum2
addq %rdx, sum2 // sum2 += 2nd half of update
.endm
// update adler/sum2 according to a new 64-byte vector
.macro DO64
imulq $$64, adler, %rdx // edx = 64*adler
movaps (buf), %xmm1 // 1st 16 bytes vector
movaps 16(buf), %xmm7 // 2nd 16 bytes vector
movaps 32(buf), %xmm10 // 3rd 16 bytes vector
movaps 48(buf), %xmm11 // 4th 16 bytes vector
movaps %xmm1, %xmm3 // 1st vector
movaps %xmm11, %xmm2 // 4th vector
psadbw zero, %xmm1 // 1st vector for adler
psadbw zero, %xmm11 // 4th vector for adler
addq %rdx, sum2 // sum2 += adler*64 pmaddubsw %xmm8, %xmm3 // 8 16-bit words to be added for sum2 : 1st vector
pmaddubsw %xmm4, %xmm2 // 8 16-bit words to be added for sum2 : 4th vector
pmaddwd ones, %xmm3 // 4 32-bit elements to be added for sum2 in xmm3
pmaddwd ones, %xmm2 // 4 32-bit elements to be added for sum2 in xmm2
paddd %xmm11, %xmm1 // 2 16-bit words to be added for adler in xmm1
paddd %xmm2, %xmm3 // 4 32-bit elements to be added for sum2 in xmm3
movaps %xmm7, %xmm2 // 2nd vector
movaps %xmm10, %xmm11 // 3rd vector
psadbw zero, %xmm7 // 2nd vector for adler
psadbw zero, %xmm10 // 3rd vector for adler
pmaddubsw %xmm9, %xmm2 // 8 16-bit words to be added for sum2 : 2nd vector
pmaddubsw %xmm6, %xmm11 // 8 16-bit words to be added for sum2 : 3rd vector
pmaddwd ones, %xmm2 // 4 32-bit elements to be added for sum2 in xmm2
pmaddwd ones, %xmm11 // 4 32-bit elements to be added for sum2 in xmm11
paddd %xmm7, %xmm1 // 2 16-bit words to be added for adler in xmm1
paddd %xmm10, %xmm1 // 2 16-bit words to be added for adler in xmm1
paddd %xmm2, %xmm3 // 4 32-bit elements to be added for sum2 in xmm3
paddd %xmm11, %xmm3 // 4 32-bit elements to be added for sum2 in xmm3
addq $$64, buf // buf -> vector for next iteration
movhlps %xmm1, %xmm2 // higher 16-bit word (for adler) in xmm2
paddq %xmm2, %xmm1 // xmm1 lower 32-bit to be added to adler
movhlps %xmm3, %xmm2 // 2 higher 32-bit elements of xmm3 to be added to lower 2 32-bit elements
movd %xmm1, %edx // to be added to adler
paddd %xmm2, %xmm3 // 2 32-bits elements in xmm3 to be added to sum2
addq %rdx, adler // update adler
movd %xmm3, %edx // to be added to sum2
psrlq $$32, %xmm3 // another 32-bit to be added to sum2
addq %rdx, sum2 // sum2 += 1st half of update
movd %xmm3, %edx // to be added to sum2
addq %rdx, sum2 // sum2 += 2nd half of update
.endm
// need to fill up xmm4/xmm5/xmm6 only if len>=16
cmpq $16, len
jl skip_loading_tables
// set up table starting address to %eax
leaq sum2_coefficients(%rip), %rax
// reading coefficients
pxor zero, zero
movaps (%rax), %xmm8 // coefficients for computing sum2 : pmaddubsw 64:49
movaps 16(%rax), %xmm9 // coefficients for computing sum2 : pmaddubsw 48:33
movaps 32(%rax), %xmm6 // coefficients for computing sum2 : pmaddubsw 32:17
movaps 48(%rax), %xmm4 // coefficients for computing sum2 : pmaddubsw 16:1
movaps 64(%rax), ones // coefficients for computing sum2 : pmaddwd 1,1,...,1
skip_loading_tables:
cmpq $NMAX, len // len vs NMAX
jl len_lessthan_NMAX // if (len < NMAX), skip the following NMAX batches processing
len_ge_NMAX_loop: // while (len>=NMAX) {
subq $NMAX, len // len -= NMAX
movq $(NMAX/64), %rax // n = NMAX/64
n_loop: // do {
DO64 // update adler/sum2 for a 64-byte input
decq %rax // n--
DO48 // update adler/sum2 for a 48-byte input
modulo_BASE // (adler/sum2) modulo BASE cmpq $NMAX, len //
jge len_ge_NMAX_loop // } /* len>=NMAX */
len_lessthan_NMAX:
subq $64, len // pre-decrement len by 64
jl len_lessthan_64 // if len < 64, skip the 64-vector code
len64_loop: // while (len>=64) {
DO64 // update adler/sum2 for a 64-byte input
subq $64, len // len -= 64
len_lessthan_64:
addq $(64-32), len // post-increment 64 + pre-decrement 32 of len
jl len_lessthan_32 // if len < 32, skip the 32-vector code
DO32 // update adler/sum2 for a 32-byte input
subq $32, len // len -= 32len_lessthan_32:
addq $(32-16), len // post-increment by 32 + pre-decrement by 16 on len
jl len_lessthan_16 // if len < 16, skip the 16-vector code
DO16 // update adler/sum2 for a 16-byte input
subq $16, len // len -= 16len_lessthan_16:
addq $16, len // post-increment len by 16
jz len_is_zero // if len==0, branch over scalar processing
scalar_loop: // while (len) {
movzbq (buf), %rdx // new input byte
incq buf // buf++
addq %rdx, adler // adler += *buf
addq adler, sum2 // sum2 += adler
decq len // len--
jg scalar_loop // }
len_is_zero:
modulo_BASE // (adler/sum2) modulo BASE // construct 32-bit (sum2<<16 | adler) to be returned
salq $16, sum2 // sum2 <<16
movq adler, %rax // adler
orq sum2, %rax // sum2<<16 | adler
#ifdef KERNEL // if for kernel, restore %xmm0-%xmm11
movaps -32(%rbp), %xmm0
movaps -48(%rbp), %xmm1
movaps -64(%rbp), %xmm2
movaps -80(%rbp), %xmm3
movaps -96(%rbp), %xmm4
movaps -112(%rbp), %xmm5
movaps -128(%rbp), %xmm6
movaps -144(%rbp), %xmm7
movaps -160(%rbp), %xmm8
movaps -176(%rbp), %xmm9
movaps -192(%rbp), %xmm10
movaps -208(%rbp), %xmm11
addq $200, %rsp // we've already restored %xmm0-%xmm11 from stack
#endif
popq %rbx
leave // pop ebp out from stack
ret
.const
.align 4
sum2_coefficients: // used for vectorizing adler32 computation
// coefficients for pmaddubsw instruction, used to generate 16-bit elements for sum2
.byte 64
.byte 63
.byte 62
.byte 61
.byte 60
.byte 59
.byte 58
.byte 57
.byte 56
.byte 55
.byte 54
.byte 53
.byte 52
.byte 51
.byte 50
.byte 49
.byte 48
.byte 47
.byte 46
.byte 45
.byte 44
.byte 43
.byte 42
.byte 41
.byte 40
.byte 39
.byte 38
.byte 37
.byte 36
.byte 35
.byte 34
.byte 33
.byte 32
.byte 31
.byte 30
.byte 29
.byte 28
.byte 27
.byte 26
.byte 25
.byte 24
.byte 23
.byte 22
.byte 21
.byte 20
.byte 19
.byte 18
.byte 17
.byte 16
.byte 15
.byte 14
.byte 13
.byte 12
.byte 11
.byte 10
.byte 9
.byte 8
.byte 7
.byte 6
.byte 5
.byte 4
.byte 3
.byte 2
.byte 1
// coefficients for pmaddwd, to combine into 4 32-bit elements for sum2
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
.word 1
#endif // (defined __i386__)
#endif // (defined __i386__ || defined __x86_64__)