text: #ifndef COSMOPOLITAN_TOOL_VIZ_LIB_CONVOLVE_H_
  #define COSMOPOLITAN_TOOL_VIZ_LIB_CONVOLVE_H_
  #include "libc/bits/xmmintrin.internal.h"
  #include "libc/str/str.h"
  #include "tool/viz/lib/graphic.h"
  #if !(__ASSEMBLER__ + __LINKER__ + 0)
  COSMOPOLITAN_C_START_
  
  forceinline void convolve(unsigned yn, unsigned xn, __m128 img[yn][xn], int KW,
                            const float kernel[KW][KW], float C1, float C2) {
    /* TODO(jart): nontemporal herringbone strategy */
    float f;
    struct Graphic g;
    unsigned y, x, i, j;
    __v4sf p, kflip[KW][KW], (*tmp)[yn][xn];
    for (i = 0; i < KW; ++i) {
      for (j = 0; j < KW; ++j) {
        f = kernel[i][j] / C1;
        kflip[KW - i - 1][KW - j - 1] = (__v4sf){f, f, f, f};
      }
    }
    memset(&g, 0, sizeof(g));
    resizegraphic(&g, yn, xn);
    tmp = g.b.p;
    for (y = 0; y < yn - KW; ++y) {
      for (x = 0; x < xn - KW; ++x) {
        memset(&p, 0, sizeof(p));
        for (i = 0; i < KW; ++i) {
          for (j = 0; j < KW; ++j) {
            p += img[y + i][x + j] * kflip[i][j] + C2;
          }
        }
        memcpy(&(*tmp)[y + KW / 2][x + KW / 2], &p, sizeof(p));
      }
    }
    memcpy(img, tmp, yn * xn * sizeof(img[0][0]));
    bfree(&g.b);
  }
  
  COSMOPOLITAN_C_END_
  #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
  #endif /* COSMOPOLITAN_TOOL_VIZ_LIB_CONVOLVE_H_ */
  