Minor issues related to builtins

[JamInJar]

Hi,

I am wrapping available builtins for ri5cy core pulpv3 extension instruction and by testing those have found some minor issues in the compiler related code:

• pulp_builtins.def
  1. lines 160-163 related to mulhh[su][R]N, prototype description should use INT instead of SHORT for arguments to match corresponding md instructions descriptions, otherwise the builtins usage leads to compile time errors;
  2. lines 179-182 same for machh[us][R]N.

• riscv-builtins.c
  1. line 339, for mac[hh][us]RN arguments check, although a norm of 0 has little interest as it becomes a simple mac[hh] the line 338 check allows it but line 339 check in such situation is machine dependent as a left shift by -1 is performed : ((1 << (Norm - 1)) == Round), a possible fix is ((Norm == 0) && (Round == 0)) || (Norm && ((1 << (Norm - 1)) == Round));
  2. line 359, same as previously but for instructions mul[hh][su]RNr, addRN[u] and subRN[u];
  3. line 398 and 408 for clip[u]_minmax, the arguments check stops with N == 29 but 30 is also a valid value, it can be reached with following fix, for (i = 0; i <= 30; i ++);
  4. lines 450-451, for invsipat1 (binsert), again although it has little interest, it is possible to insert a full 32b data at offset 0 (so to perform a move), the mask being in such a case 0xffffffff. This means that the computed size for the mask is 32 and this value is then used in a lshift in integer context so the result might be machine dependent. Also if mask is 0 and offset is also 0, no error is issued but the resulting instructions issued are hazardeous (sorry I have not captured them ...). One way to fix this check is :
  if ((MaskBar == ~Mask) && (Offset <= 31) && Mask && ((Size == 32)? (Mask == 0xffffffff) : ((unsigned int) (((1<<Size) - 1) << Offset) == Mask))) return 1;
  5. lines 463, 465, 470, 472, 477, 479, 484, 486, 491, 493, 498, 500, 505, 507, the valid CSR addresses range from 0 to 4095 ^^.

• riscv.c
  1. lines 2587 and 2591, report clip modification to allow N == 30;
  2. line 2608, add checks :
  if (!val && !val1) return 1; if (!val) return 0;
  to align with all norm and round from immediate args modification.

All suggested modifications have been implemented and tested.

Thank you !