libwebp/src/dsp/rescaler_mips_dsp_r2.c
Pascal Massimino 7df93893dc fix rescaling bug (uninitialized read, see bug #254).
the x_add/x_sub increments were wrong for u/v in the upscaling case.
They shouldn't be left to the caller's discretion, but set up by
WebPRescalerInit to their exact necessary values.

-> Cleaned-up WebPRescalerInit() param list.
-> added safety asserts
-> removed the mips32/mips_r2 variant of "ImportRow" which were buggy prior

Change-Id: I347c75804d835811e7025de92a0758d7929dfc09
2015-08-05 23:00:00 -07:00

119 lines
5.9 KiB
C

// Copyright 2014 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// MIPS version of rescaling functions
//
// Author(s): Djordje Pesut (djordje.pesut@imgtec.com)
#include "./dsp.h"
#if defined(WEBP_USE_MIPS_DSP_R2)
#include "../utils/rescaler.h"
static void ExportRow(WebPRescaler* const wrk, int x_out) {
if (wrk->y_accum <= 0) {
// if wrk->fxy_scale can fit into 32 bits use optimized code,
// otherwise use C code
if ((wrk->fxy_scale >> 32) == 0) {
uint8_t* dst = wrk->dst;
int32_t* irow = wrk->irow;
const int32_t* frow = wrk->frow;
const int yscale = wrk->fy_scale * (-wrk->y_accum);
const int x_out_max = wrk->dst_width * wrk->num_channels;
int temp0, temp1, temp3, temp4, temp5, temp6, temp7;
const int temp2 = (int)wrk->fxy_scale;
const int rest = (x_out_max - x_out) & 1;
const int32_t* const loop_end = frow + (x_out_max - x_out) - rest;
__asm__ volatile (
".set push \n\t"
".set noreorder \n\t"
"beq %[frow], %[loop_end], 1f \n\t"
" nop \n\t"
"0: \n\t"
"lw %[temp0], 0(%[frow]) \n\t"
"lw %[temp1], 0(%[irow]) \n\t"
"lw %[temp3], 4(%[frow]) \n\t"
"lw %[temp4], 4(%[irow]) \n\t"
"sll %[temp0], %[temp0], 1 \n\t"
"sll %[temp3], %[temp3], 1 \n\t"
"mulq_rs.w %[temp5], %[temp0], %[yscale] \n\t"
"mulq_rs.w %[temp6], %[temp3], %[yscale] \n\t"
"addiu %[frow], %[frow], 8 \n\t"
"addiu %[dst], %[dst], 2 \n\t"
"addiu %[irow], %[irow], 8 \n\t"
"subu %[temp1], %[temp1], %[temp5] \n\t"
"subu %[temp4], %[temp4], %[temp6] \n\t"
"sll %[temp1], %[temp1], 1 \n\t"
"sll %[temp4], %[temp4], 1 \n\t"
"mulq_rs.w %[temp0], %[temp1], %[temp2] \n\t"
"mulq_rs.w %[temp3], %[temp4], %[temp2] \n\t"
"sw %[temp5], -8(%[irow]) \n\t"
"sw %[temp6], -4(%[irow]) \n\t"
"shll_s.ph %[temp0], %[temp0], 7 \n\t"
"shll_s.ph %[temp3], %[temp3], 7 \n\t"
"precrqu_s.qb.ph %[temp0], %[temp0], %[temp3] \n\t"
"sb %[temp0], -1(%[dst]) \n\t"
"srl %[temp0], %[temp0], 16 \n\t"
"bne %[frow], %[loop_end], 0b \n\t"
" sb %[temp0], -2(%[dst]) \n\t"
"1: \n\t"
"beqz %[rest], 3f \n\t"
" nop \n\t"
"addiu %[temp6], $zero, -256 \n\t"
"addiu %[temp7], $zero, 255 \n\t"
"lw %[temp0], 0(%[frow]) \n\t"
"sll %[temp0], %[temp0], 1 \n\t"
"mulq_rs.w %[temp1], %[temp0], %[yscale] \n\t"
"lw %[temp0], 0(%[irow]) \n\t"
"subu %[temp0], %[temp0], %[temp1] \n\t"
"sll %[temp0], %[temp0], 1 \n\t"
"mulq_rs.w %[temp5], %[temp0], %[temp2] \n\t"
"sw %[temp1], 0(%[irow]) \n\t"
"and %[temp0], %[temp5], %[temp6] \n\t"
"beqz %[temp0], 2f \n\t"
" slti %[temp1], %[temp5], 0 \n\t"
"xor %[temp5], %[temp5], %[temp5] \n\t"
"movz %[temp5], %[temp7], %[temp1] \n\t"
"2: \n\t"
"sb %[temp5], 0(%[dst]) \n\t"
"3: \n\t"
".set pop \n\t"
: [temp0]"=&r"(temp0), [temp1]"=&r"(temp1), [temp3]"=&r"(temp3),
[temp4]"=&r"(temp4), [temp5]"=&r"(temp5), [temp6]"=&r"(temp6),
[temp7]"=&r"(temp7), [frow]"+&r"(frow), [irow]"+&r"(irow),
[dst]"+&r"(dst)
: [temp2]"r"(temp2), [yscale]"r"(yscale), [loop_end]"r"(loop_end),
[rest]"r"(rest)
: "memory", "hi", "lo"
);
wrk->y_accum += wrk->y_add;
wrk->dst += wrk->dst_stride;
} else {
WebPRescalerExportRowC(wrk, x_out);
}
}
}
//------------------------------------------------------------------------------
// Entry point
extern void WebPRescalerDspInitMIPSdspR2(void);
WEBP_TSAN_IGNORE_FUNCTION void WebPRescalerDspInitMIPSdspR2(void) {
WebPRescalerExportRow = ExportRow;
}
#else // !WEBP_USE_MIPS_DSP_R2
WEBP_DSP_INIT_STUB(WebPRescalerDspInitMIPSdspR2)
#endif // WEBP_USE_MIPS_DSP_R2