implement unsigned -> float casts
amd64 lacks an instruction for this so it has to be implemented with signed -> float casts: - Word casting is done by zero-extending the word to a long and then doing a regular signed cast. - Long casting is done by dividing by two with correct rounding if the highest bit is set and casting that to float, then adding 1 to mantissa with integer addition
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b0d27d8a01
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6 changed files with 107 additions and 5 deletions
45
amd64/isel.c
45
amd64/isel.c
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@ -201,8 +201,8 @@ selcmp(Ref arg[2], int k, int swap, Fn *fn)
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static void
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sel(Ins i, ANum *an, Fn *fn)
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{
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Ref r0, r1;
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int x, k, kc, swap;
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Ref r0, r1, tmp[7];
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int x, j, k, kc, swap;
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int64_t sz;
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Ins *i0, *i1;
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@ -266,6 +266,47 @@ sel(Ins i, ANum *an, Fn *fn)
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emit(Ocopy, Kw, TMP(RCX), r0, R);
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fixarg(&i1->arg[0], argcls(&i, 0), i1, fn);
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break;
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case Ouwtof:
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r0 = newtmp("utof", Kl, fn);
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emit(Osltof, k, i.to, r0, R);
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emit(Oextuw, Kl, r0, i.arg[0], R);
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fixarg(&curi->arg[0], k, curi, fn);
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break;
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case Oultof:
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/*
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%mask =l and %arg.0, 1
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%isbig =l shr %arg.0, 63
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%divided =l shr %arg.0, %isbig
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%or =l or %mask, %divided
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%float =d sltof %or
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%cast =l cast %float
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%addend =l shl %isbig, 52
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%sum =l add %cast, %addend
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%result =d cast %sum
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*/
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r0 = newtmp("utof", k, fn);
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if (k == Ks)
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kc = Kw;
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else
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kc = Kl;
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for (j=0; j<4; j++)
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tmp[j] = newtmp("utof", Kl, fn);
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for (; j<7; j++)
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tmp[j] = newtmp("utof", kc, fn);
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emit(Ocast, k, i.to, tmp[6], R);
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emit(Oadd, kc, tmp[6], tmp[4], tmp[5]);
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emit(Oshl, kc, tmp[5], tmp[1], getcon(k == Ks ? 23 : 52, fn));
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emit(Ocast, kc, tmp[4], r0, R);
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emit(Osltof, k, r0, tmp[3], R);
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emit(Oor, Kl, tmp[3], tmp[0], tmp[2]);
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emit(Oshr, Kl, tmp[2], i.arg[0], tmp[1]);
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sel(*curi++, an, fn);
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emit(Oshr, Kl, tmp[1], i.arg[0], getcon(63, fn));
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fixarg(&curi->arg[0], Kl, curi, fn);
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emit(Oand, Kl, tmp[0], i.arg[0], getcon(1, fn));
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fixarg(&curi->arg[0], Kl, curi, fn);
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break;
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case Onop:
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break;
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case Ostored:
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