-rw-r--r-- 5434 saferewrite-20210904/src/decode_761x1531/portable/decode.c
/* auto-generated; do not edit */

#include "crypto_decode.h"
#include "crypto_int16.h"
#include "crypto_uint16.h"
#include "crypto_uint32.h"
#include "crypto_uint64.h"
#define int16 crypto_int16
#define uint16 crypto_uint16
#define uint32 crypto_uint32
#define uint64 crypto_uint64

/*
CPU division instruction typically takes time depending on x.
This software is designed to take time independent of x.
Time still varies depending on m; user must ensure that m is constant.
Time also varies on CPUs where multiplication is variable-time.
There could be more CPU issues.
There could also be compiler issues. 
*/

static void uint32_divmod_uint14(uint32 *q,uint16 *r,uint32 x,uint16 m)
{
  uint32 v = 0x80000000;
  uint32 qpart;
  uint32 mask;

  v /= m;

  /* caller guarantees m > 0 */
  /* caller guarantees m < 16384 */
  /* vm <= 2^31 <= vm+m-1 */
  /* xvm <= 2^31 x <= xvm+x(m-1) */

  *q = 0;

  qpart = (x*(uint64)v)>>31;
  /* 2^31 qpart <= xv <= 2^31 qpart + 2^31-1 */
  /* 2^31 qpart m <= xvm <= 2^31 qpart m + (2^31-1)m */
  /* 2^31 qpart m <= 2^31 x <= 2^31 qpart m + (2^31-1)m + x(m-1) */
  /* 0 <= 2^31 newx <= (2^31-1)m + x(m-1) */
  /* 0 <= newx <= (1-1/2^31)m + x(m-1)/2^31 */
  /* 0 <= newx <= (1-1/2^31)(2^14-1) + (2^32-1)((2^14-1)-1)/2^31 */

  x -= qpart*m; *q += qpart;
  /* x <= 49146 */

  qpart = (x*(uint64)v)>>31;
  /* 0 <= newx <= (1-1/2^31)m + x(m-1)/2^31 */
  /* 0 <= newx <= m + 49146(2^14-1)/2^31 */
  /* 0 <= newx <= m + 0.4 */
  /* 0 <= newx <= m */

  x -= qpart*m; *q += qpart;
  /* x <= m */

  x -= m; *q += 1;
  mask = -(x>>31);
  x += mask&(uint32)m; *q += mask;
  /* x < m */

  *r = x;
}

static uint16 uint32_mod_uint14(uint32 x,uint16 m)
{
  uint32 q;
  uint16 r;
  uint32_divmod_uint14(&q,&r,x,m);
  return r;
}

void crypto_decode(void *v,const unsigned char *s)
{
  int16 *R0 = v;
  uint16 R1[381],R2[191],R3[96],R4[48],R5[24],R6[12],R7[6],R8[3],R9[2],R10[1];
  long long i;
  uint16 r0;
  uint32 r1,r2;
  
  s += crypto_decode_STRBYTES;
  r1 = 0;
  r1 = (r1<<8)|*--s;
  r1 = (r1<<8)|*--s;
  r1 = uint32_mod_uint14(r1,3475); /* needed only for invalid inputs */
  R10[0] = r1;
  
  r2 = R10[0];
  r2 = (r2<<8)|*--s;
  uint32_divmod_uint14(&r1,&r0,r2,593);
  R9[0] = r0;
  r1 = uint32_mod_uint14(r1,1500); /* needed only for invalid inputs */
  R9[1] = r1;
  
  R8[2] = R9[1];
  r2 = R9[0];
  r2 = (r2<<8)|*--s;
  r2 = (r2<<8)|*--s;
  uint32_divmod_uint14(&r1,&r0,r2,6232);
  R8[0] = r0;
  r1 = uint32_mod_uint14(r1,6232); /* needed only for invalid inputs */
  R8[1] = r1;
  
  r2 = R8[2];
  r2 = (r2<<8)|*--s;
  uint32_divmod_uint14(&r1,&r0,r2,1263);
  R7[4] = r0;
  r1 = uint32_mod_uint14(r1,304); /* needed only for invalid inputs */
  R7[5] = r1;
  for (i = 1;i >= 0;--i) {
    r2 = R8[i];
    r2 = (r2<<8)|*--s;
    uint32_divmod_uint14(&r1,&r0,r2,1263);
    R7[2*i] = r0;
    r1 = uint32_mod_uint14(r1,1263); /* needed only for invalid inputs */
    R7[2*i+1] = r1;
  }
  
  r2 = R7[5];
  r2 = (r2<<8)|*--s;
  r2 = (r2<<8)|*--s;
  uint32_divmod_uint14(&r1,&r0,r2,9097);
  R6[10] = r0;
  r1 = uint32_mod_uint14(r1,2188); /* needed only for invalid inputs */
  R6[11] = r1;
  for (i = 4;i >= 0;--i) {
    r2 = R7[i];
    r2 = (r2<<8)|*--s;
    r2 = (r2<<8)|*--s;
    uint32_divmod_uint14(&r1,&r0,r2,9097);
    R6[2*i] = r0;
    r1 = uint32_mod_uint14(r1,9097); /* needed only for invalid inputs */
    R6[2*i+1] = r1;
  }
  
  r2 = R6[11];
  r2 = (r2<<8)|*--s;
  uint32_divmod_uint14(&r1,&r0,r2,1526);
  R5[22] = r0;
  r1 = uint32_mod_uint14(r1,367); /* needed only for invalid inputs */
  R5[23] = r1;
  for (i = 10;i >= 0;--i) {
    r2 = R6[i];
    r2 = (r2<<8)|*--s;
    uint32_divmod_uint14(&r1,&r0,r2,1526);
    R5[2*i] = r0;
    r1 = uint32_mod_uint14(r1,1526); /* needed only for invalid inputs */
    R5[2*i+1] = r1;
  }
  
  r2 = R5[23];
  r2 = (r2<<8)|*--s;
  uint32_divmod_uint14(&r1,&r0,r2,625);
  R4[46] = r0;
  r1 = uint32_mod_uint14(r1,150); /* needed only for invalid inputs */
  R4[47] = r1;
  for (i = 22;i >= 0;--i) {
    r2 = R5[i];
    r2 = (r2<<8)|*--s;
    uint32_divmod_uint14(&r1,&r0,r2,625);
    R4[2*i] = r0;
    r1 = uint32_mod_uint14(r1,625); /* needed only for invalid inputs */
    R4[2*i+1] = r1;
  }
  
  r2 = R4[47];
  r2 = (r2<<8)|*--s;
  r2 = (r2<<8)|*--s;
  uint32_divmod_uint14(&r1,&r0,r2,6400);
  R3[94] = r0;
  r1 = uint32_mod_uint14(r1,1531); /* needed only for invalid inputs */
  R3[95] = r1;
  for (i = 46;i >= 0;--i) {
    r2 = R4[i];
    r2 = (r2<<8)|*--s;
    r2 = (r2<<8)|*--s;
    uint32_divmod_uint14(&r1,&r0,r2,6400);
    R3[2*i] = r0;
    r1 = uint32_mod_uint14(r1,6400); /* needed only for invalid inputs */
    R3[2*i+1] = r1;
  }
  
  R2[190] = R3[95];
  for (i = 94;i >= 0;--i) {
    r2 = R3[i];
    r2 = (r2<<8)|*--s;
    uint32_divmod_uint14(&r1,&r0,r2,1280);
    R2[2*i] = r0;
    r1 = uint32_mod_uint14(r1,1280); /* needed only for invalid inputs */
    R2[2*i+1] = r1;
  }
  
  R1[380] = R2[190];
  for (i = 189;i >= 0;--i) {
    r2 = R2[i];
    r2 = (r2<<8)|*--s;
    r2 = (r2<<8)|*--s;
    uint32_divmod_uint14(&r1,&r0,r2,9157);
    R1[2*i] = r0;
    r1 = uint32_mod_uint14(r1,9157); /* needed only for invalid inputs */
    R1[2*i+1] = r1;
  }
  
  R0[760] = 3*R1[380]-2295;
  for (i = 379;i >= 0;--i) {
    r2 = R1[i];
    r2 = (r2<<8)|*--s;
    uint32_divmod_uint14(&r1,&r0,r2,1531);
    R0[2*i] = 3*r0-2295;
    r1 = uint32_mod_uint14(r1,1531); /* needed only for invalid inputs */
    R0[2*i+1] = 3*r1-2295;
  }
}