[Flac-dev] altivec lpc_restore_signal

Brady Patterson brady at spaceship.com
Mon Sep 15 23:52:04 PDT 2003


I've had this a long time but haven't submitted it yet.

I've tried to mirror the ia32 setup, so there should be a new subdirectory
src/libFLAC/ppc . The first two attachments go there. The third is a context
diff for src/libFLAC/Makefile.am .

I have some more modified files, which I figured I'd submit after the above
are checked in and working for somebody other than me. If you would prefer me
to submit them all at once, let me know.

I've tested this some and am reasonably confident of it. It seems to provide
a decent performance improvement for decoding.

--
Brady Patterson (brady at spaceship.com)
Give us the Destruct-O-Beam!
-------------- next part --------------
; $Name$ $Revision$ $Date$

.text
	.align 2
.globl _FLAC__lpc_restore_signal_asm_ppc_altivec_16
.globl _FLAC__lpc_restore_signal_asm_ppc_altivec_16_order8

_FLAC__lpc_restore_signal_asm_ppc_altivec_16:
;	r3: residual[]
;	r4: data_len
;	r5: qlp_coeff[]
;	r6: order
;	r7: lp_quantization
;	r8: data[]

; see src/libFLAC/lpc.c:FLAC__lpc_restore_signal()
; these is a PowerPC/Altivec assembly version which requires bps<=16 (or actual
; bps<=15 for mid-side coding, since that uses an extra bit)

; these should be fast; the inner loop is unrolled (it takes no more than
; 3*(order%4) instructions, all of which are arithmetic), and all of the
; coefficients and all relevant history stay in registers, so the outer loop
; has only one load from memory (the residual)

; I haven't yet run this through simg4, so there may be some avoidable stalls,
; and there may be a somewhat more clever way to do the outer loop

; the branch mechanism may prevent dynamic loading; I still need to examine
; this issue, and there may be a more elegant method

	stmw r31,-4(r1)

	addi r9,r1,-28
	li r31,0xf
	andc r9,r9,r31 ; for quadword-aligned stack data

	slwi r6,r6,2 ; adjust for word size
	slwi r4,r4,2
	add r4,r4,r8 ; r4 = data+data_len

	mfspr r0,256 ; cache old vrsave
	addis r31,0,hi16(0xfffffc00)
	ori r31,r31,lo16(0xfffffc00)
	mtspr 256,r31 ; declare VRs in vrsave

	cmplw cr0,r8,r4 ; i<data_len
	bc 4,0,L1400

	; load coefficients into v0-v7 and initial history into v8-v15
	li r31,0xf
	and r31,r8,r31 ; r31: data%4
	li r11,16
	subf r31,r31,r11 ; r31: 4-(data%4)
	slwi r31,r31,3 ; convert to bits for vsro
	li r10,-4
	stw r31,-4(r9)
	lvewx v0,r10,r9
	vspltisb v18,-1
	vsro v18,v18,v0 ; v18: mask vector

	li r31,0x8
	lvsl v0,0,r31
	vsldoi v0,v0,v0,12
	li r31,0xc
	lvsl v1,0,r31
	vspltisb v2,0
	vspltisb v3,-1
	vmrglw v2,v2,v3
	vsel v0,v1,v0,v2 ; v0: reversal permutation vector

	add r10,r5,r6
	lvsl v17,0,r5 ; v17: coefficient alignment permutation vector
	vperm v17,v17,v17,v0 ; v17: reversal coefficient alignment permutation vector

	mr r11,r8
	lvsl v16,0,r11 ; v16: history alignment permutation vector

	lvx v0,0,r5
	addi r5,r5,16
	lvx v1,0,r5
	vperm v0,v0,v1,v17
	lvx v8,0,r11
	addi r11,r11,-16
	lvx v9,0,r11
	vperm v8,v9,v8,v16
	cmplw cr0,r5,r10
	bc 12,0,L1101
	vand v0,v0,v18
	addis r31,0,hi16(L1307)
	ori r31,r31,lo16(L1307)
	b L1199

L1101:
	addi r5,r5,16
	lvx v2,0,r5
	vperm v1,v1,v2,v17
	addi r11,r11,-16
	lvx v10,0,r11
	vperm v9,v10,v9,v16
	cmplw cr0,r5,r10
	bc 12,0,L1102
	vand v1,v1,v18
	addis r31,0,hi16(L1306)
	ori r31,r31,lo16(L1306)
	b L1199

L1102:
	addi r5,r5,16
	lvx v3,0,r5
	vperm v2,v2,v3,v17
	addi r11,r11,-16
	lvx v11,0,r11
	vperm v10,v11,v10,v16
	cmplw cr0,r5,r10
	bc 12,0,L1103
	vand v2,v2,v18
	addis r31,0,hi16(L1305)
	ori r31,r31,lo16(L1305)
	b L1199

L1103:
	addi r5,r5,16
	lvx v4,0,r5
	vperm v3,v3,v4,v17
	addi r11,r11,-16
	lvx v12,0,r11
	vperm v11,v12,v11,v16
	cmplw cr0,r5,r10
	bc 12,0,L1104
	vand v3,v3,v18
	addis r31,0,hi16(L1304)
	ori r31,r31,lo16(L1304)
	b L1199

L1104:
	addi r5,r5,16
	lvx v5,0,r5
	vperm v4,v4,v5,v17
	addi r11,r11,-16
	lvx v13,0,r11
	vperm v12,v13,v12,v16
	cmplw cr0,r5,r10
	bc 12,0,L1105
	vand v4,v4,v18
	addis r31,0,hi16(L1303)
	ori r31,r31,lo16(L1303)
	b L1199

L1105:
	addi r5,r5,16
	lvx v6,0,r5
	vperm v5,v5,v6,v17
	addi r11,r11,-16
	lvx v14,0,r11
	vperm v13,v14,v13,v16
	cmplw cr0,r5,r10
	bc 12,0,L1106
	vand v5,v5,v18
	addis r31,0,hi16(L1302)
	ori r31,r31,lo16(L1302)
	b L1199

L1106:
	addi r5,r5,16
	lvx v7,0,r5
	vperm v6,v6,v7,v17
	addi r11,r11,-16
	lvx v15,0,r11
	vperm v14,v15,v14,v16
	cmplw cr0,r5,r10
	bc 12,0,L1107
	vand v6,v6,v18
	addis r31,0,hi16(L1301)
	ori r31,r31,lo16(L1301)
	b L1199

L1107:
	addi r5,r5,16
	lvx v19,0,r5
	vperm v7,v7,v19,v17
	addi r11,r11,-16
	lvx v19,0,r11
	vperm v15,v19,v15,v16
	vand v7,v7,v18
	addis r31,0,hi16(L1300)
	ori r31,r31,lo16(L1300)

L1199:
	mtctr r31

	; set up invariant vectors
	vspltish v16,0 ; v16: zero vector

	li r10,-12
	lvsr v17,r10,r8 ; v17: result shift vector
	lvsl v18,r10,r3 ; v18: residual shift back vector

	li r10,-4
	stw r7,-4(r9)
	lvewx v19,r10,r9 ; v19: lp_quantization vector

L1200:
	vmulosh v20,v0,v8 ; v20: sum vector
	bcctr 20,0

L1300:
	vmulosh v21,v7,v15
	vsldoi v15,v15,v14,4 ; increment history
	vaddsws v20,v20,v21

L1301:
	vmulosh v21,v6,v14
	vsldoi v14,v14,v13,4
	vaddsws v20,v20,v21

L1302:
	vmulosh v21,v5,v13
	vsldoi v13,v13,v12,4
	vaddsws v20,v20,v21

L1303:
	vmulosh v21,v4,v12
	vsldoi v12,v12,v11,4
	vaddsws v20,v20,v21

L1304:
	vmulosh v21,v3,v11
	vsldoi v11,v11,v10,4
	vaddsws v20,v20,v21

L1305:
	vmulosh v21,v2,v10
	vsldoi v10,v10,v9,4
	vaddsws v20,v20,v21

L1306:
	vmulosh v21,v1,v9
	vsldoi v9,v9,v8,4
	vaddsws v20,v20,v21

L1307:
	vsumsws v20,v20,v16 ; v20[3]: sum
	vsraw v20,v20,v19 ; v20[3]: sum >> lp_quantization

	lvewx v21,0,r3 ; v21[n]: *residual
	vperm v21,v21,v21,v18 ; v21[3]: *residual
	vaddsws v20,v21,v20 ; v20[3]: *residual + (sum >> lp_quantization)
	vsldoi v18,v18,v18,4 ; increment shift vector

	vperm v21,v20,v20,v17 ; v21[n]: shift for storage
	vsldoi v17,v17,v17,12 ; increment shift vector
	stvewx v21,0,r8

	vsldoi v20,v20,v20,12
	vsldoi v8,v8,v20,4 ; insert value onto history

	addi r3,r3,4
	addi r8,r8,4
	cmplw cr0,r8,r4 ; i<data_len
	bc 12,0,L1200

L1400:
	mtspr 256,r0 ; restore old vrsave
	lmw r31,-4(r1)
	blr

_FLAC__lpc_restore_signal_asm_ppc_altivec_16_order8:
;	r3: residual[]
;	r4: data_len
;	r5: qlp_coeff[]
;	r6: order
;	r7: lp_quantization
;	r8: data[]

; see _FLAC__lpc_restore_signal_asm_ppc_altivec_16() above
; this version assumes order<=8; it uses fewer vector registers, which should
; save time in context switches, and has less code, which may improve
; instruction caching

	stmw r31,-4(r1)

	addi r9,r1,-28
	li r31,0xf
	andc r9,r9,r31 ; for quadword-aligned stack data

	slwi r6,r6,2 ; adjust for word size
	slwi r4,r4,2
	add r4,r4,r8 ; r4 = data+data_len

	mfspr r0,256 ; cache old vrsave
	addis r31,0,hi16(0xffc00000)
	ori r31,r31,lo16(0xffc00000)
	mtspr 256,r31 ; declare VRs in vrsave

	cmplw cr0,r8,r4 ; i<data_len
	bc 4,0,L2400

	; load coefficients into v0-v1 and initial history into v2-v3
	li r31,0xf
	and r31,r8,r31 ; r31: data%4
	li r11,16
	subf r31,r31,r11 ; r31: 4-(data%4)
	slwi r31,r31,3 ; convert to bits for vsro
	li r10,-4
	stw r31,-4(r9)
	lvewx v0,r10,r9
	vspltisb v6,-1
	vsro v6,v6,v0 ; v6: mask vector

	li r31,0x8
	lvsl v0,0,r31
	vsldoi v0,v0,v0,12
	li r31,0xc
	lvsl v1,0,r31
	vspltisb v2,0
	vspltisb v3,-1
	vmrglw v2,v2,v3
	vsel v0,v1,v0,v2 ; v0: reversal permutation vector

	add r10,r5,r6
	lvsl v5,0,r5 ; v5: coefficient alignment permutation vector
	vperm v5,v5,v5,v0 ; v5: reversal coefficient alignment permutation vector

	mr r11,r8
	lvsl v4,0,r11 ; v4: history alignment permutation vector

	lvx v0,0,r5
	addi r5,r5,16
	lvx v1,0,r5
	vperm v0,v0,v1,v5
	lvx v2,0,r11
	addi r11,r11,-16
	lvx v3,0,r11
	vperm v2,v3,v2,v4
	cmplw cr0,r5,r10
	bc 12,0,L2101
	vand v0,v0,v6
	addis r31,0,hi16(L2301)
	ori r31,r31,lo16(L2301)
	b L2199

L2101:
	addi r5,r5,16
	lvx v7,0,r5
	vperm v1,v1,v7,v5
	addi r11,r11,-16
	lvx v7,0,r11
	vperm v3,v7,v3,v4
	vand v1,v1,v6
	addis r31,0,hi16(L2300)
	ori r31,r31,lo16(L2300)

L2199:
	mtctr r31

	; set up invariant vectors
	vspltish v4,0 ; v4: zero vector

	li r10,-12
	lvsr v5,r10,r8 ; v5: result shift vector
	lvsl v6,r10,r3 ; v6: residual shift back vector

	li r10,-4
	stw r7,-4(r9)
	lvewx v7,r10,r9 ; v7: lp_quantization vector

L2200:
	vmulosh v8,v0,v2 ; v8: sum vector
	bcctr 20,0

L2300:
	vmulosh v9,v1,v3
	vsldoi v3,v3,v2,4
	vaddsws v8,v8,v9

L2301:
	vsumsws v8,v8,v4 ; v8[3]: sum
	vsraw v8,v8,v7 ; v8[3]: sum >> lp_quantization

	lvewx v9,0,r3 ; v9[n]: *residual
	vperm v9,v9,v9,v6 ; v9[3]: *residual
	vaddsws v8,v9,v8 ; v8[3]: *residual + (sum >> lp_quantization)
	vsldoi v6,v6,v6,4 ; increment shift vector

	vperm v9,v8,v8,v5 ; v9[n]: shift for storage
	vsldoi v5,v5,v5,12 ; increment shift vector
	stvewx v9,0,r8

	vsldoi v8,v8,v8,12
	vsldoi v2,v2,v8,4 ; insert value onto history

	addi r3,r3,4
	addi r8,r8,4
	cmplw cr0,r8,r4 ; i<data_len
	bc 12,0,L2200

L2400:
	mtspr 256,r0 ; restore old vrsave
	lmw r31,-4(r1)
	blr
-------------- next part --------------

SUFFIXES = .s .lo

.s.lo:
	$(LIBTOOL) --mode=compile as -force_cpusubtype_ALL -o $@ $<

noinst_LTLIBRARIES = libFLAC-asm.la
libFLAC_asm_la_SOURCES = \
	lpc_asm.s
-------------- next part --------------
Index: Makefile.am
===================================================================
RCS file: /cvsroot/flac/flac/src/libFLAC/Makefile.am,v
retrieving revision 1.44
diff -c -r1.44 Makefile.am
*** Makefile.am 27 May 2003 05:07:16 -0000      1.44
--- Makefile.am 16 Sep 2003 06:34:15 -0000
***************
*** 44,49 ****
--- 44,53 ----
  libFLAC_la_LIBADD = -lm
  endif
  endif
+ if FLaC__CPU_PPC
+ ARCH_SUBDIRS = ppc
+ libFLAC_la_LIBADD = ppc/libFLAC-asm.la
+ endif
  endif
  
  SUBDIRS = $(ARCH_SUBDIRS) include .


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