19c791cdac
With rare exceptions ...
- Always separate line continuation characters by one space from
preceding code.
- Always use two-space indentation. Never use tabs.
- Always use K&R-style conditional blocks.
- Always surround operators with spaces, except in raw assembly code.
- Always put a space after, but not before, a comma.
- Never put a space between type casts and variables/function calls.
- Never put a space between the function name and the argument list in
function declarations and prototypes.
- Always surround braces ('{' and '}') with spaces.
- Always surround statements (if, for, else, catch, while, do, switch)
with spaces.
- Always attach pointer symbols ('*' and '**') to the variable or
function name.
- Always precede pointer symbols ('*' and '**') by a space in type
casts.
- Use the MIN() macro from jpegint.h within the libjpeg and TurboJPEG
API libraries (using min() from tjutil.h is still necessary for
TJBench.)
- Where it makes sense (particularly in the TurboJPEG code), put a blank
line after variable declaration blocks.
- Always separate statements in one-liners by two spaces.
The purpose of this was to ease maintenance on my part and also to make
it easier for contributors to figure out how to format patch
submissions. This was admittedly confusing (even to me sometimes) when
we had 3 or 4 different style conventions in the same source tree. The
new convention is more consistent with the formatting of other OSS code
bases.
This commit corrects deviations from the chosen formatting style in the
libjpeg API code and reformats the TurboJPEG API code such that it
conforms to the same standard.
NOTES:
- Although it is no longer necessary for the function name in function
declarations to begin in Column 1 (this was historically necessary
because of the ansi2knr utility, which allowed libjpeg to be built
with non-ANSI compilers), we retain that formatting for the libjpeg
code because it improves readability when using libjpeg's function
attribute macros (GLOBAL(), etc.)
- This reformatting project was accomplished with the help of AStyle and
Uncrustify, although neither was completely up to the task, and thus
a great deal of manual tweaking was required. Note to developers of
code formatting utilities: the libjpeg-turbo code base is an
excellent test bed, because AFAICT, it breaks every single one of the
utilities that are currently available.
- The legacy (MMX, SSE, 3DNow!) assembly code for i386 has been
formatted to match the SSE2 code (refer to
ff5685d5344273df321eb63a005eaae19d2496e3.) I hadn't intended to
bother with this, but the Loongson MMI implementation demonstrated
that there is still academic value to the MMX implementation, as an
algorithmic model for other 64-bit vector implementations. Thus, it
is desirable to improve its readability in the same manner as that of
the SSE2 implementation.
155 lines
4.4 KiB
C
155 lines
4.4 KiB
C
/*
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* AltiVec optimizations for libjpeg-turbo
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*
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* Copyright (C) 2014, D. R. Commander. All Rights Reserved.
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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/* FAST INTEGER FORWARD DCT
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*
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* This is similar to the SSE2 implementation, except that we left-shift the
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* constants by 1 less bit (the -1 in CONST_SHIFT.) This is because
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* vec_madds(arg1, arg2, arg3) generates the 16-bit saturated sum of:
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* the elements in arg3 + the most significant 17 bits of
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* (the elements in arg1 * the elements in arg2).
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*/
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#include "jsimd_altivec.h"
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#define F_0_382 98 /* FIX(0.382683433) */
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#define F_0_541 139 /* FIX(0.541196100) */
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#define F_0_707 181 /* FIX(0.707106781) */
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#define F_1_306 334 /* FIX(1.306562965) */
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#define CONST_BITS 8
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#define PRE_MULTIPLY_SCALE_BITS 2
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#define CONST_SHIFT (16 - PRE_MULTIPLY_SCALE_BITS - CONST_BITS - 1)
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#define DO_FDCT() { \
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/* Even part */ \
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\
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tmp10 = vec_add(tmp0, tmp3); \
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tmp13 = vec_sub(tmp0, tmp3); \
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tmp11 = vec_add(tmp1, tmp2); \
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tmp12 = vec_sub(tmp1, tmp2); \
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\
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out0 = vec_add(tmp10, tmp11); \
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out4 = vec_sub(tmp10, tmp11); \
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\
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z1 = vec_add(tmp12, tmp13); \
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z1 = vec_sl(z1, pre_multiply_scale_bits); \
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z1 = vec_madds(z1, pw_0707, pw_zero); \
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\
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out2 = vec_add(tmp13, z1); \
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out6 = vec_sub(tmp13, z1); \
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\
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/* Odd part */ \
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\
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tmp10 = vec_add(tmp4, tmp5); \
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tmp11 = vec_add(tmp5, tmp6); \
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tmp12 = vec_add(tmp6, tmp7); \
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\
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tmp10 = vec_sl(tmp10, pre_multiply_scale_bits); \
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tmp12 = vec_sl(tmp12, pre_multiply_scale_bits); \
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z5 = vec_sub(tmp10, tmp12); \
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z5 = vec_madds(z5, pw_0382, pw_zero); \
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\
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z2 = vec_madds(tmp10, pw_0541, z5); \
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z4 = vec_madds(tmp12, pw_1306, z5); \
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\
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tmp11 = vec_sl(tmp11, pre_multiply_scale_bits); \
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z3 = vec_madds(tmp11, pw_0707, pw_zero); \
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\
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z11 = vec_add(tmp7, z3); \
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z13 = vec_sub(tmp7, z3); \
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\
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out5 = vec_add(z13, z2); \
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out3 = vec_sub(z13, z2); \
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out1 = vec_add(z11, z4); \
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out7 = vec_sub(z11, z4); \
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}
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void jsimd_fdct_ifast_altivec(DCTELEM *data)
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{
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__vector short row0, row1, row2, row3, row4, row5, row6, row7,
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col0, col1, col2, col3, col4, col5, col6, col7,
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tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp10, tmp11, tmp12, tmp13,
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z1, z2, z3, z4, z5, z11, z13,
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out0, out1, out2, out3, out4, out5, out6, out7;
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/* Constants */
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__vector short pw_zero = { __8X(0) },
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pw_0382 = { __8X(F_0_382 << CONST_SHIFT) },
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pw_0541 = { __8X(F_0_541 << CONST_SHIFT) },
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pw_0707 = { __8X(F_0_707 << CONST_SHIFT) },
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pw_1306 = { __8X(F_1_306 << CONST_SHIFT) };
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__vector unsigned short
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pre_multiply_scale_bits = { __8X(PRE_MULTIPLY_SCALE_BITS) };
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/* Pass 1: process rows */
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row0 = vec_ld(0, data);
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row1 = vec_ld(16, data);
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row2 = vec_ld(32, data);
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row3 = vec_ld(48, data);
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row4 = vec_ld(64, data);
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row5 = vec_ld(80, data);
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row6 = vec_ld(96, data);
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row7 = vec_ld(112, data);
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TRANSPOSE(row, col);
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tmp0 = vec_add(col0, col7);
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tmp7 = vec_sub(col0, col7);
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tmp1 = vec_add(col1, col6);
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tmp6 = vec_sub(col1, col6);
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tmp2 = vec_add(col2, col5);
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tmp5 = vec_sub(col2, col5);
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tmp3 = vec_add(col3, col4);
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tmp4 = vec_sub(col3, col4);
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DO_FDCT();
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/* Pass 2: process columns */
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TRANSPOSE(out, row);
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tmp0 = vec_add(row0, row7);
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tmp7 = vec_sub(row0, row7);
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tmp1 = vec_add(row1, row6);
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tmp6 = vec_sub(row1, row6);
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tmp2 = vec_add(row2, row5);
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tmp5 = vec_sub(row2, row5);
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tmp3 = vec_add(row3, row4);
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tmp4 = vec_sub(row3, row4);
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DO_FDCT();
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vec_st(out0, 0, data);
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vec_st(out1, 16, data);
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vec_st(out2, 32, data);
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vec_st(out3, 48, data);
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vec_st(out4, 64, data);
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vec_st(out5, 80, data);
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vec_st(out6, 96, data);
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vec_st(out7, 112, data);
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}
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