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0004-Add-portable-fallbacks-for-__builtin_clz-ll.patch (1136B)

    

  1. From b87edf043bc03527ac702d1fdc678e930f77a082 Mon Sep 17 00:00:00 2001
  2. From: Michael Forney <mforney@mforney.org>
  3. Date: Mon, 6 Sep 2021 19:55:08 -0700
  4. Subject: [PATCH] Add portable fallbacks for __builtin_clz[ll]
  6. ---
  7.  softfp.c | 26 ++++++++++++++++++++++++++
  8.  1 file changed, 26 insertions(+)
  10. diff --git a/softfp.c b/softfp.c
  11. index 2a1aad0..801ecc3 100644
  12. --- a/softfp.c
  13. +++ b/softfp.c
  14. @@ -35,7 +35,25 @@ static inline int clz32(uint32_t a)
  15.      if (a == 0) {
  16.          r = 32;
  17.      } else {
  18. +#ifdef __GNUC__
  19.          r = __builtin_clz(a);
  20. +#else
  21. +	int t;
  22. +
  23. +	t = ((a & 0xffff0000) == 0) << 4;
  24. +	a >>= 16 - t;
  25. +	r = t;
  26. +	t = ((a & 0xff00) == 0) << 3;
  27. +	a >>= 8 - t;
  28. +	r |= t;
  29. +	t = ((a & 0xf0) == 0) << 2;
  30. +	a >>= 4 - t;
  31. +	r |= t;
  32. +	t = ((a & 0xc) == 0) << 1;
  33. +	a >>= 2 - t;
  34. +	r |= t;
  35. +	r += 2 - a & -((a & 2) == 0);
  36. +#endif
  37.      }
  38.      return r;
  39.  }
  40. @@ -47,7 +65,15 @@ static inline int clz64(uint64_t a)
  41.          r = 64;
  42.      } else 
  43.      {
  44. +#ifdef __GNUC__
  45.          r = __builtin_clzll(a);
  46. +#else
  47. +	int t;
  48. +
  49. +	t = ((a & 0xffffffff00000000) == 0) << 8;
  50. +	a >>= 32 - t;
  51. +	r = t | clz32(a);
  52. +#endif
  53.      }
  54.      return r;
  55.  }
  56. -- 
  57. 2.32.0