Update libjpeg_turbo to 1.4.90 from https://github.com/libjpeg-turbo/

jccolor.c

 /*
  * jccolor.c
  *
  * This file was part of the Independent JPEG Group's software:
  * Copyright (C) 1991-1996, Thomas G. Lane.
  * libjpeg-turbo Modifications:
  * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
- * Copyright (C) 2009-2012, D. R. Commander.
- * For conditions of distribution and use, see the accompanying README file.
+ * Copyright (C) 2009-2012, 2015 D. R. Commander.
+ * Copyright (C) 2014, MIPS Technologies, Inc., California
+ * For conditions of distribution and use, see the accompanying README.ijg
+ * file.
  *
  * This file contains input colorspace conversion routines.
  */
 
 #define JPEG_INTERNALS
 #include "jinclude.h"
 #include "jpeglib.h"
 #include "jsimd.h"
-#include "config.h"
+#include "jconfigint.h"
 
 
 /* Private subobject */
 
 typedef struct {
   struct jpeg_color_converter pub; /* public fields */
 
   /* Private state for RGB->YCC conversion */
-  INT32 * rgb_ycc_tab;          /* => table for RGB to YCbCr conversion */
+  JLONG *rgb_ycc_tab;           /* => table for RGB to YCbCr conversion */
 } my_color_converter;
 
-typedef my_color_converter * my_cconvert_ptr;
+typedef my_color_converter *my_cconvert_ptr;
 
 
 /**************** RGB -> YCbCr conversion: most common case **************/
 
 /*
  * YCbCr is defined per CCIR 601-1, except that Cb and Cr are
  * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
  * The conversion equations to be implemented are therefore
- *      Y  =  0.29900 * R + 0.58700 * G + 0.11400 * B
- *      Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B  + CENTERJSAMPLE
- *      Cr =  0.50000 * R - 0.41869 * G - 0.08131 * B  + CENTERJSAMPLE
+ *      Y  =  0.29900 * R + 0.58700 * G + 0.11400 * B
+ *      Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B  + CENTERJSAMPLE
+ *      Cr =  0.50000 * R - 0.41869 * G - 0.08131 * B  + CENTERJSAMPLE
  * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
  * Note: older versions of the IJG code used a zero offset of MAXJSAMPLE/2,
  * rather than CENTERJSAMPLE, for Cb and Cr.  This gave equal positive and
  * negative swings for Cb/Cr, but meant that grayscale values (Cb=Cr=0)
  * were not represented exactly.  Now we sacrifice exact representation of
  * maximum red and maximum blue in order to get exact grayscales.
  *
  * To avoid floating-point arithmetic, we represent the fractional constants
  * as integers scaled up by 2^16 (about 4 digits precision); we have to divide
  * the products by 2^16, with appropriate rounding, to get the correct answer.
  *
  * For even more speed, we avoid doing any multiplications in the inner loop
  * by precalculating the constants times R,G,B for all possible values.
  * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
  * for 12-bit samples it is still acceptable.  It's not very reasonable for
  * 16-bit samples, but if you want lossless storage you shouldn't be changing
  * colorspace anyway.
  * The CENTERJSAMPLE offsets and the rounding fudge-factor of 0.5 are included
  * in the tables to save adding them separately in the inner loop.
  */
 
-#define SCALEBITS       16      /* speediest right-shift on some machines */
-#define CBCR_OFFSET     ((INT32) CENTERJSAMPLE << SCALEBITS)
-#define ONE_HALF        ((INT32) 1 << (SCALEBITS-1))
-#define FIX(x)          ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
+#define SCALEBITS       16      /* speediest right-shift on some machines */
+#define CBCR_OFFSET     ((JLONG) CENTERJSAMPLE << SCALEBITS)
+#define ONE_HALF        ((JLONG) 1 << (SCALEBITS-1))
+#define FIX(x)          ((JLONG) ((x) * (1L<<SCALEBITS) + 0.5))
 
 /* We allocate one big table and divide it up into eight parts, instead of
  * doing eight alloc_small requests.  This lets us use a single table base
  * address, which can be held in a register in the inner loops on many
  * machines (more than can hold all eight addresses, anyway).
  */
 
-#define R_Y_OFF         0                       /* offset to R => Y section */
-#define G_Y_OFF         (1*(MAXJSAMPLE+1))      /* offset to G => Y section */
-#define B_Y_OFF         (2*(MAXJSAMPLE+1))      /* etc. */
-#define R_CB_OFF        (3*(MAXJSAMPLE+1))
-#define G_CB_OFF        (4*(MAXJSAMPLE+1))
-#define B_CB_OFF        (5*(MAXJSAMPLE+1))
-#define R_CR_OFF        B_CB_OFF                /* B=>Cb, R=>Cr are the same */
-#define G_CR_OFF        (6*(MAXJSAMPLE+1))
-#define B_CR_OFF        (7*(MAXJSAMPLE+1))
-#define TABLE_SIZE      (8*(MAXJSAMPLE+1))
+#define R_Y_OFF         0                       /* offset to R => Y section */
+#define G_Y_OFF         (1*(MAXJSAMPLE+1))      /* offset to G => Y section */
+#define B_Y_OFF         (2*(MAXJSAMPLE+1))      /* etc. */
+#define R_CB_OFF        (3*(MAXJSAMPLE+1))
+#define G_CB_OFF        (4*(MAXJSAMPLE+1))
+#define B_CB_OFF        (5*(MAXJSAMPLE+1))
+#define R_CR_OFF        B_CB_OFF                /* B=>Cb, R=>Cr are the same */
+#define G_CR_OFF        (6*(MAXJSAMPLE+1))
+#define B_CR_OFF        (7*(MAXJSAMPLE+1))
+#define TABLE_SIZE      (8*(MAXJSAMPLE+1))
 
 
 /* Include inline routines for colorspace extensions */
 
 #include "jccolext.c"
 #undef RGB_RED
 #undef RGB_GREEN
 #undef RGB_BLUE
 #undef RGB_PIXELSIZE
 
@@ skipping 95 matching lines @@
 
 
 /*
  * Initialize for RGB->YCC colorspace conversion.
  */
 
 METHODDEF(void)
 rgb_ycc_start (j_compress_ptr cinfo)
 {
   my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
-  INT32 * rgb_ycc_tab;
-  INT32 i;
+  JLONG *rgb_ycc_tab;
+  JLONG i;
 
   /* Allocate and fill in the conversion tables. */
-  cconvert->rgb_ycc_tab = rgb_ycc_tab = (INT32 *)
+  cconvert->rgb_ycc_tab = rgb_ycc_tab = (JLONG *)
     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
-                                (TABLE_SIZE * SIZEOF(INT32)));
+                                (TABLE_SIZE * sizeof(JLONG)));
 
   for (i = 0; i <= MAXJSAMPLE; i++) {
     rgb_ycc_tab[i+R_Y_OFF] = FIX(0.29900) * i;
     rgb_ycc_tab[i+G_Y_OFF] = FIX(0.58700) * i;
     rgb_ycc_tab[i+B_Y_OFF] = FIX(0.11400) * i     + ONE_HALF;
     rgb_ycc_tab[i+R_CB_OFF] = (-FIX(0.16874)) * i;
     rgb_ycc_tab[i+G_CB_OFF] = (-FIX(0.33126)) * i;
     /* We use a rounding fudge-factor of 0.5-epsilon for Cb and Cr.
      * This ensures that the maximum output will round to MAXJSAMPLE
      * not MAXJSAMPLE+1, and thus that we don't have to range-limit.
      */
     rgb_ycc_tab[i+B_CB_OFF] = FIX(0.50000) * i    + CBCR_OFFSET + ONE_HALF-1;
 /*  B=>Cb and R=>Cr tables are the same
     rgb_ycc_tab[i+R_CR_OFF] = FIX(0.50000) * i    + CBCR_OFFSET + ONE_HALF-1;
 */
     rgb_ycc_tab[i+G_CR_OFF] = (-FIX(0.41869)) * i;
     rgb_ycc_tab[i+B_CR_OFF] = (-FIX(0.08131)) * i;
   }
 }
 
 
 /*
  * Convert some rows of samples to the JPEG colorspace.
  */
 
 METHODDEF(void)
 rgb_ycc_convert (j_compress_ptr cinfo,
-                 JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
-                 JDIMENSION output_row, int num_rows)
+                 JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+                 JDIMENSION output_row, int num_rows)
 {
   switch (cinfo->in_color_space) {
     case JCS_EXT_RGB:
       extrgb_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
                                   num_rows);
       break;
     case JCS_EXT_RGBX:
     case JCS_EXT_RGBA:
       extrgbx_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
                                    num_rows);
@@ skipping 27 matching lines @@
 
 /**************** Cases other than RGB -> YCbCr **************/
 
 
 /*
  * Convert some rows of samples to the JPEG colorspace.
  */
 
 METHODDEF(void)
 rgb_gray_convert (j_compress_ptr cinfo,
-                  JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
-                  JDIMENSION output_row, int num_rows)
+                  JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+                  JDIMENSION output_row, int num_rows)
 {
   switch (cinfo->in_color_space) {
     case JCS_EXT_RGB:
       extrgb_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
                                    num_rows);
       break;
     case JCS_EXT_RGBX:
     case JCS_EXT_RGBA:
       extrgbx_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
                                     num_rows);
@@ skipping 24 matching lines @@
   }
 }
 
 
 /*
  * Extended RGB to plain RGB conversion
  */
 
 METHODDEF(void)
 rgb_rgb_convert (j_compress_ptr cinfo,
-                  JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
-                  JDIMENSION output_row, int num_rows)
+                  JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+                  JDIMENSION output_row, int num_rows)
 {
   switch (cinfo->in_color_space) {
     case JCS_EXT_RGB:
       extrgb_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
                                   num_rows);
       break;
     case JCS_EXT_RGBX:
     case JCS_EXT_RGBA:
       extrgbx_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
                                    num_rows);
@@ skipping 28 matching lines @@
 /*
  * Convert some rows of samples to the JPEG colorspace.
  * This version handles Adobe-style CMYK->YCCK conversion,
  * where we convert R=1-C, G=1-M, and B=1-Y to YCbCr using the same
  * conversion as above, while passing K (black) unchanged.
  * We assume rgb_ycc_start has been called.
  */
 
 METHODDEF(void)
 cmyk_ycck_convert (j_compress_ptr cinfo,
-                   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
-                   JDIMENSION output_row, int num_rows)
+                   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+                   JDIMENSION output_row, int num_rows)
 {
   my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
   register int r, g, b;
-  register INT32 * ctab = cconvert->rgb_ycc_tab;
+  register JLONG *ctab = cconvert->rgb_ycc_tab;
   register JSAMPROW inptr;
   register JSAMPROW outptr0, outptr1, outptr2, outptr3;
   register JDIMENSION col;
   JDIMENSION num_cols = cinfo->image_width;
 
   while (--num_rows >= 0) {
     inptr = *input_buf++;
     outptr0 = output_buf[0][output_row];
     outptr1 = output_buf[1][output_row];
     outptr2 = output_buf[2][output_row];
     outptr3 = output_buf[3][output_row];
     output_row++;
     for (col = 0; col < num_cols; col++) {
       r = MAXJSAMPLE - GETJSAMPLE(inptr[0]);
       g = MAXJSAMPLE - GETJSAMPLE(inptr[1]);
       b = MAXJSAMPLE - GETJSAMPLE(inptr[2]);
       /* K passes through as-is */
-      outptr3[col] = inptr[3];  /* don't need GETJSAMPLE here */
+      outptr3[col] = inptr[3];  /* don't need GETJSAMPLE here */
       inptr += 4;
       /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
        * must be too; we do not need an explicit range-limiting operation.
        * Hence the value being shifted is never negative, and we don't
        * need the general RIGHT_SHIFT macro.
        */
       /* Y */
       outptr0[col] = (JSAMPLE)
-                ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
-                 >> SCALEBITS);
+                ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
+                 >> SCALEBITS);
       /* Cb */
       outptr1[col] = (JSAMPLE)
-                ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
-                 >> SCALEBITS);
+                ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
+                 >> SCALEBITS);
       /* Cr */
       outptr2[col] = (JSAMPLE)
-                ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
-                 >> SCALEBITS);
+                ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
+                 >> SCALEBITS);
     }
   }
 }
 
 
 /*
  * Convert some rows of samples to the JPEG colorspace.
  * This version handles grayscale output with no conversion.
  * The source can be either plain grayscale or YCbCr (since Y == gray).
  */
 
 METHODDEF(void)
 grayscale_convert (j_compress_ptr cinfo,
-                   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
-                   JDIMENSION output_row, int num_rows)
+                   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+                   JDIMENSION output_row, int num_rows)
 {
   register JSAMPROW inptr;
   register JSAMPROW outptr;
   register JDIMENSION col;
   JDIMENSION num_cols = cinfo->image_width;
   int instride = cinfo->input_components;
 
   while (--num_rows >= 0) {
     inptr = *input_buf++;
     outptr = output_buf[0][output_row];
     output_row++;
     for (col = 0; col < num_cols; col++) {
-      outptr[col] = inptr[0];   /* don't need GETJSAMPLE() here */
+      outptr[col] = inptr[0];   /* don't need GETJSAMPLE() here */
       inptr += instride;
     }
   }
 }
 
 
 /*
  * Convert some rows of samples to the JPEG colorspace.
  * This version handles multi-component colorspaces without conversion.
  * We assume input_components == num_components.
  */
 
 METHODDEF(void)
 null_convert (j_compress_ptr cinfo,
-              JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
-              JDIMENSION output_row, int num_rows)
+              JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+              JDIMENSION output_row, int num_rows)
 {
   register JSAMPROW inptr;
-  register JSAMPROW outptr;
+  register JSAMPROW outptr, outptr0, outptr1, outptr2, outptr3;
   register JDIMENSION col;
   register int ci;
   int nc = cinfo->num_components;
   JDIMENSION num_cols = cinfo->image_width;
 
-  while (--num_rows >= 0) {
-    /* It seems fastest to make a separate pass for each component. */
-    for (ci = 0; ci < nc; ci++) {
-      inptr = *input_buf;
-      outptr = output_buf[ci][output_row];
+  if (nc == 3) {
+    while (--num_rows >= 0) {
+      inptr = *input_buf++;
+      outptr0 = output_buf[0][output_row];
+      outptr1 = output_buf[1][output_row];
+      outptr2 = output_buf[2][output_row];
+      output_row++;
       for (col = 0; col < num_cols; col++) {
-        outptr[col] = inptr[ci]; /* don't need GETJSAMPLE() here */
-        inptr += nc;
+        outptr0[col] = *inptr++;
+        outptr1[col] = *inptr++;
+        outptr2[col] = *inptr++;
       }
     }
-    input_buf++;
-    output_row++;
+  } else if (nc == 4) {
+    while (--num_rows >= 0) {
+      inptr = *input_buf++;
+      outptr0 = output_buf[0][output_row];
+      outptr1 = output_buf[1][output_row];
+      outptr2 = output_buf[2][output_row];
+      outptr3 = output_buf[3][output_row];
+      output_row++;
+      for (col = 0; col < num_cols; col++) {
+        outptr0[col] = *inptr++;
+        outptr1[col] = *inptr++;
+        outptr2[col] = *inptr++;
+        outptr3[col] = *inptr++;
+      }
+    }
+  } else {
+    while (--num_rows >= 0) {
+      /* It seems fastest to make a separate pass for each component. */
+      for (ci = 0; ci < nc; ci++) {
+        inptr = *input_buf;
+        outptr = output_buf[ci][output_row];
+        for (col = 0; col < num_cols; col++) {
+          outptr[col] = inptr[ci]; /* don't need GETJSAMPLE() here */
+          inptr += nc;
+        }
+      }
+      input_buf++;
+      output_row++;
+    }
   }
 }
 
 
 /*
  * Empty method for start_pass.
  */
 
 METHODDEF(void)
 null_method (j_compress_ptr cinfo)
 {
   /* no work needed */
 }
 
 
 /*
  * Module initialization routine for input colorspace conversion.
  */
 
 GLOBAL(void)
 jinit_color_converter (j_compress_ptr cinfo)
 {
   my_cconvert_ptr cconvert;
 
   cconvert = (my_cconvert_ptr)
     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
-                                SIZEOF(my_color_converter));
+                                sizeof(my_color_converter));
   cinfo->cconvert = (struct jpeg_color_converter *) cconvert;
   /* set start_pass to null method until we find out differently */
   cconvert->pub.start_pass = null_method;
 
   /* Make sure input_components agrees with in_color_space */
   switch (cinfo->in_color_space) {
   case JCS_GRAYSCALE:
     if (cinfo->input_components != 1)
       ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
     break;
@@ skipping 17 matching lines @@
     if (cinfo->input_components != 3)
       ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
     break;
 
   case JCS_CMYK:
   case JCS_YCCK:
     if (cinfo->input_components != 4)
       ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
     break;
 
-  default:                      /* JCS_UNKNOWN can be anything */
+  default:                      /* JCS_UNKNOWN can be anything */
     if (cinfo->input_components < 1)
       ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
     break;
   }
 
   /* Check num_components, set conversion method based on requested space */
   switch (cinfo->jpeg_color_space) {
   case JCS_GRAYSCALE:
     if (cinfo->num_components != 1)
       ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
@@ skipping 21 matching lines @@
     else
       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
     break;
 
   case JCS_RGB:
     if (cinfo->num_components != 3)
       ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
     if (rgb_red[cinfo->in_color_space] == 0 &&
         rgb_green[cinfo->in_color_space] == 1 &&
         rgb_blue[cinfo->in_color_space] == 2 &&
-        rgb_pixelsize[cinfo->in_color_space] == 3)
-      cconvert->pub.color_convert = null_convert;
-    else if (cinfo->in_color_space == JCS_RGB ||
-             cinfo->in_color_space == JCS_EXT_RGB ||
-             cinfo->in_color_space == JCS_EXT_RGBX ||
-             cinfo->in_color_space == JCS_EXT_BGR ||
-             cinfo->in_color_space == JCS_EXT_BGRX ||
-             cinfo->in_color_space == JCS_EXT_XBGR ||
-             cinfo->in_color_space == JCS_EXT_XRGB ||
-             cinfo->in_color_space == JCS_EXT_RGBA ||
-             cinfo->in_color_space == JCS_EXT_BGRA ||
-             cinfo->in_color_space == JCS_EXT_ABGR ||
-             cinfo->in_color_space == JCS_EXT_ARGB)
+        rgb_pixelsize[cinfo->in_color_space] == 3) {
+#if defined(__mips__)
+      if (jsimd_c_can_null_convert())
+        cconvert->pub.color_convert = jsimd_c_null_convert;
+      else
+#endif
+        cconvert->pub.color_convert = null_convert;
+    } else if (cinfo->in_color_space == JCS_RGB ||
+               cinfo->in_color_space == JCS_EXT_RGB ||
+               cinfo->in_color_space == JCS_EXT_RGBX ||
+               cinfo->in_color_space == JCS_EXT_BGR ||
+               cinfo->in_color_space == JCS_EXT_BGRX ||
+               cinfo->in_color_space == JCS_EXT_XBGR ||
+               cinfo->in_color_space == JCS_EXT_XRGB ||
+               cinfo->in_color_space == JCS_EXT_RGBA ||
+               cinfo->in_color_space == JCS_EXT_BGRA ||
+               cinfo->in_color_space == JCS_EXT_ABGR ||
+               cinfo->in_color_space == JCS_EXT_ARGB)
       cconvert->pub.color_convert = rgb_rgb_convert;
     else
       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
     break;
 
   case JCS_YCbCr:
     if (cinfo->num_components != 3)
       ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
     if (cinfo->in_color_space == JCS_RGB ||
         cinfo->in_color_space == JCS_EXT_RGB ||
         cinfo->in_color_space == JCS_EXT_RGBX ||
         cinfo->in_color_space == JCS_EXT_BGR ||
         cinfo->in_color_space == JCS_EXT_BGRX ||
         cinfo->in_color_space == JCS_EXT_XBGR ||
         cinfo->in_color_space == JCS_EXT_XRGB ||
         cinfo->in_color_space == JCS_EXT_RGBA ||
         cinfo->in_color_space == JCS_EXT_BGRA ||
         cinfo->in_color_space == JCS_EXT_ABGR ||
         cinfo->in_color_space == JCS_EXT_ARGB) {
       if (jsimd_can_rgb_ycc())
         cconvert->pub.color_convert = jsimd_rgb_ycc_convert;
       else {
         cconvert->pub.start_pass = rgb_ycc_start;
         cconvert->pub.color_convert = rgb_ycc_convert;
       }
-    } else if (cinfo->in_color_space == JCS_YCbCr)
-      cconvert->pub.color_convert = null_convert;
-    else
+    } else if (cinfo->in_color_space == JCS_YCbCr) {
+#if defined(__mips__)
+      if (jsimd_c_can_null_convert())
+        cconvert->pub.color_convert = jsimd_c_null_convert;
+      else
+#endif
+        cconvert->pub.color_convert = null_convert;
+    } else
       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
     break;
 
   case JCS_CMYK:
     if (cinfo->num_components != 4)
       ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
-    if (cinfo->in_color_space == JCS_CMYK)
-      cconvert->pub.color_convert = null_convert;
-    else
+    if (cinfo->in_color_space == JCS_CMYK) {
+#if defined(__mips__)
+      if (jsimd_c_can_null_convert())
+        cconvert->pub.color_convert = jsimd_c_null_convert;
+      else
+#endif
+        cconvert->pub.color_convert = null_convert;
+    } else
       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
     break;
 
   case JCS_YCCK:
     if (cinfo->num_components != 4)
       ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
     if (cinfo->in_color_space == JCS_CMYK) {
       cconvert->pub.start_pass = rgb_ycc_start;
       cconvert->pub.color_convert = cmyk_ycck_convert;
-    } else if (cinfo->in_color_space == JCS_YCCK)
-      cconvert->pub.color_convert = null_convert;
-    else
+    } else if (cinfo->in_color_space == JCS_YCCK) {
+#if defined(__mips__)
+      if (jsimd_c_can_null_convert())
+        cconvert->pub.color_convert = jsimd_c_null_convert;
+      else
+#endif
+        cconvert->pub.color_convert = null_convert;
+    } else
       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
     break;
 
-  default:                      /* allow null conversion of JCS_UNKNOWN */
+  default:                      /* allow null conversion of JCS_UNKNOWN */
     if (cinfo->jpeg_color_space != cinfo->in_color_space ||
-        cinfo->num_components != cinfo->input_components)
+        cinfo->num_components != cinfo->input_components)
       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
-    cconvert->pub.color_convert = null_convert;
+#if defined(__mips__)
+    if (jsimd_c_can_null_convert())
+      cconvert->pub.color_convert = jsimd_c_null_convert;
+    else
+#endif
+      cconvert->pub.color_convert = null_convert;
     break;
   }
 }