| author | pcpa <paulo.cesar.pereira.de.andrade@gmail.com> | 2023年02月28日 08:38:39 -0300 |
|---|---|---|
| committer | pcpa <paulo.cesar.pereira.de.andrade@gmail.com> | 2023年02月28日 08:38:39 -0300 |
| commit | 6180f53ad2f51f41741a61c0bef7be22de5a8e3e (patch) | |
| tree | d806ff761b4bd1ead78a0808f48d41e322831753 | |
| parent | b769ab6e1f5c00101af31a1d211f1ce738a2e687 (diff) | |
| download | lightning-6180f53ad2f51f41741a61c0bef7be22de5a8e3e.tar.gz | |
| -rw-r--r-- | lib/jit_fallback.c | 103 |
diff --git a/lib/jit_fallback.c b/lib/jit_fallback.c index ca9db02..cb593fa 100644 --- a/lib/jit_fallback.c +++ b/lib/jit_fallback.c @@ -1,4 +1,5 @@ #if PROTO +#define USE_BIT_TABLES 1 #define fallback_save(r0) _fallback_save(_jit, r0) static void _fallback_save(jit_state_t*, jit_int32_t); #define fallback_load(r0) _fallback_load(_jit, r0) @@ -265,6 +266,51 @@ _fallback_clo(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1) static void _fallback_clz(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1) { +# if USE_BIT_TABLES + /* t0 = __WORDSIZE - 8; + * loop: + * t1 = r1 >> t0; + * if (t1) + * goto done; + * t0 -= 8; + * if (t0) + * goto loop; + * t1 = r1; + * done: + * r0 = __WORDSIZE - 8 - t0 + clz_tab[t1] + */ + /* Table below is count of leading zeros of 8 bit values. */ + static const jit_uint8_t clz_tab[256] = { + 8,7,6,6,5,5,5,5,4,4,4,4,4,4,4,4,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, + 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, + 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 + }; + jit_int32_t t0, t1; + jit_word_t loop, done; + t0 = jit_get_reg(jit_class_gpr); + t1 = jit_get_reg(jit_class_gpr); + movi(rn(t0), __WORDSIZE - 8); + fallback_flush(); + loop = _jit->pc.w; + rshr_u(rn(t1), r1, rn(t0)); + done = fallback_bnei(_jit->pc.w, rn(t1), 0); + subi(rn(t0), rn(t0), 8); + fallback_bnei(loop, rn(t0), 0); + movr(rn(t1), r1); + fallback_flush(); + fallback_patch_bnei(done, _jit->pc.w); + rsbi(r0, rn(t0), __WORDSIZE - 8); + movi(rn(t0), (jit_word_t)clz_tab); + ldxr_uc(rn(t1), rn(t0), rn(t1)); + addr(r0, r0, rn(t1)); + jit_unget_reg(t1); + jit_unget_reg(t0); +# else jit_int32_t r1_reg, r2, r2_reg; jit_word_t clz, l32, l16, l8, l4, l2, l1; l32 = fallback_bnei(_jit->pc.w, r1, 0); @@ -278,7 +324,7 @@ _fallback_clz(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1) movr(rn(r1_reg), r1); r1 = rn(r1_reg); movi(r0, 0); -# if __WORDSIZE == 64 +# if __WORDSIZE == 64 movi(r2, 0xffffffff00000000UL); l32 = fallback_bmsr(_jit->pc.w, r1, r2); lshi(r1, r1, 32); @@ -286,9 +332,9 @@ _fallback_clz(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1) fallback_flush(); fallback_patch_bmsr(l32, _jit->pc.w); lshi(r2, r2, 16); -# else +# else movi(r2, 0xffff0000UL); -# endif +# endif l16 = fallback_bmsr(_jit->pc.w, r1, r2); lshi(r1, r1, 16); addi(r0, r0, 16); @@ -320,6 +366,7 @@ _fallback_clz(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1) fallback_patch_jmpi(clz, _jit->pc.w); jit_unget_reg(r2_reg); jit_unget_reg(r1_reg); +# endif } static void @@ -340,6 +387,49 @@ _fallback_cto(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1) static void _fallback_ctz(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1) { +# if USE_BIT_TABLES + /* Adapted from http://graphics.stanford.edu/~seander/bithacks.html#ZerosOnRightModLookup + * Table for 64 bits was recomputed choosing 67 as next prime number. + * The cost of the modulo might not compensate and could be better to + * use the alternate version (or bitswap and use clz). + */ + jit_int32_t t0; +# if __WORDSIZE == 32 + static const jit_uint8_t mod37[] = { + 32, 0, 1, 26, 2, 23, 27, 0, 3, 16, 24, 30, 28, 11, 0, 13, + 4, 7, 17, 0, 25, 22, 31, 15, 29, 10, 12, 6, 0, 21, 14, 9, + 5, 20, 8, 19, 18 + }; + /* return mod37[(-r1 & r1) % 37]; */ +# else + static const jit_uint8_t mod67[] = { + 64, 0, 1, 39, 2, 15, 40, 23, 3, 12, 16, 59, 41, 19, 24, 54, + 4, 0, 13, 10, 17, 62, 60, 28, 42, 30, 20, 51, 25, 44, 55, 47, + 5, 32, 0, 38, 14, 22, 11, 58, 18, 53, 63, 9, 61, 27, 29, 50, + 43, 46, 31, 37, 21, 57, 52, 8, 26, 49, 45, 36, 56, 7, 48, 35, + 6, 34, 33 + }; + /* return mod67[(-r1 & r1) % 67]; */ +# endif + t0 = jit_get_reg(jit_class_gpr); + if (r0 == r1) { + negr(rn(t0), r1); + andr(r0, rn(t0), r1); + } + else { + negr(r0, r1); + andr(r0, r0, r1); + } +# if __WORDSIZE == 32 + remi_u(r0, r0, 37); + movi(rn(t0), (jit_word_t)mod37); +# else + remi_u(r0, r0, 67); + movi(rn(t0), (jit_word_t)mod67); +# endif + ldxr_uc(r0, rn(t0), r0); + jit_unget_reg(t0); +# else jit_int32_t r1_reg, r2, r2_reg; jit_word_t ctz, l32, l16, l8, l4, l2, l1; l32 = fallback_bnei(_jit->pc.w, r1, 0); @@ -353,7 +443,7 @@ _fallback_ctz(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1) movr(rn(r1_reg), r1); r1 = rn(r1_reg); movi(r0, 0); -# if __WORDSIZE == 64 +# if __WORDSIZE == 64 movi(r2, 0xffffffffUL); l32 = fallback_bmsr(_jit->pc.w, r1, r2); rshi_u(r1, r1, 32); @@ -361,9 +451,9 @@ _fallback_ctz(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1) fallback_flush(); fallback_patch_bmsr(l32, _jit->pc.w); rshi(r2, r2, 16); -# else +# else movi(r2, 0xffffUL); -# endif +# endif l16 = fallback_bmsr(_jit->pc.w, r1, r2); rshi_u(r1, r1, 16); addi(r0, r0, 16); @@ -395,5 +485,6 @@ _fallback_ctz(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1) fallback_patch_jmpi(ctz, _jit->pc.w); jit_unget_reg(r2_reg); jit_unget_reg(r1_reg); +# endif } #endif |