nimvm bug workaround

stint/modular_arithmetic.nim

@@ -113,13 +113,6 @@ func mulmod*(a, b, m: StUint): StUint =
 func powmod*(a, b, m: StUint): StUint =
   ## Modular exponentiation
 
-  when nimvm:
-    doAssert false, "cannot use powmod at compile-time"
-  else:
-    # we need this ugly branch
-    # because of nim-lang/Nim#12517
-    discard
-
   let a_m = if a < m: a
             else: a mod m
 

stint/private/uint_div.nim

@@ -47,7 +47,7 @@ func shlAddMod_multi(a: var openArray[Word], c: Word,
                      M: openArray[Word], mBits: int): Word =
   ## Fused modular left-shift + add
   ## Shift input `a` by a word and add `c` modulo `M`
-  ## 
+  ##
   ## Specialized for M being a multi-precision integer.
   ##
   ## With a word W = 2^WordBitWidth and a modulus M
@@ -55,7 +55,7 @@ func shlAddMod_multi(a: var openArray[Word], c: Word,
   ## and returns q = (a * W + c ) / M
   ##
   ## The modulus `M` most-significant bit at `mBits` MUST be set.
-  
+
                                         # Assuming 64-bit words
   let hi = a[^1]                        # Save the high word to detect carries
   let R = mBits and (WordBitWidth - 1)  # R = mBits mod 64
@@ -128,7 +128,7 @@ func shlAddMod(a: var openArray[Word], c: Word,
                M: openArray[Word], mBits: int): Word {.inline.}=
   ## Fused modular left-shift + add
   ## Shift input `a` by a word and add `c` modulo `M`
-  ## 
+  ##
   ## With a word W = 2^WordBitWidth and a modulus M
   ## Does a <- a * W + c (mod M)
   ## and returns q = (a * W + c ) / M
@@ -182,13 +182,28 @@ func divRem*(
     copyWords(r, 0, a, aOffset+1, bLen-1)
     r[rLen-1] = 0
     # Now shift-left the copied words while adding the new word mod b
-    for i in countdown(aOffset, 0):
-      q[i] = shlAddMod(
-        r.toOpenArray(0, rLen-1),
-        a[i],
-        b.toOpenArray(0, bLen-1),
-        bBits
-      )
+
+    when nimvm:
+      # workaround nim bug #22095
+      var rr = @(r.toOpenArray(0, rLen-1))
+      var bb = @(b.toOpenArray(0, bLen-1))
+      for i in countdown(aOffset, 0):
+        q[i] = shlAddMod(
+          rr,
+          a[i],
+          bb,
+          bBits
+        )
+      for i in 0..rLen-1:
+        r[i] = rr[i]
+    else:
+      for i in countdown(aOffset, 0):
+        q[i] = shlAddMod(
+          r.toOpenArray(0, rLen-1),
+          a[i],
+          b.toOpenArray(0, bLen-1),
+          bBits
+        )
 
     # Clean up extra words
     for i in aOffset+1 ..< q.len:
@@ -229,7 +244,7 @@ func divRem*(
 # - An Efficient Multiple-Precision Division Algorithm,
 #   Liusheng Huang, Hong Zhong, Hong Shen, Yonglong Luo, 2005
 #   https://ieeexplore.ieee.org/document/1579076
-# 
+#
 # - Efficient multiple-precision integer division algorithm
 #   Debapriyay Mukhopadhyaya, Subhas C.Nandy, 2014
 #   https://www.sciencedirect.com/science/article/abs/pii/S0020019013002627

tests/test_int_muldiv.nim

@@ -116,8 +116,8 @@ template testMuldiv(chk, tst: untyped) =
     chkMod(chk, 2, -5, 2, 64)
     chkMod(chk, -2, -5, -2, 64)
 
-#static:
-  #testMuldiv(ctCheck, ctTest)
+static:
+  testMuldiv(ctCheck, ctTest)
 
 suite "Wider signed int muldiv coverage":
   testMuldiv(check, test)

tests/test_uint_divmod.nim

@@ -60,8 +60,8 @@ template testdivmod(chk, tst: untyped) =
     chkDivMod(chk, "FFFFFFFFFFFFFFFF", "27", "690690690690690", "F", 128)
     chkDivMod(chk, "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "27", "6906906906906906906906906906906", "15", 128)
 
-#static:
-  #testdivmod(ctCheck, ctTest)
+static:
+  testdivmod(ctCheck, ctTest)
 
 suite "Wider unsigned int muldiv coverage":
   testdivmod(check, test)

tests/test_uint_modular_arithmetic.nim

@@ -56,8 +56,8 @@ template testModArith(chk, tst: untyped) =
     chkPowMod(chk, "FFFFFFFFFFFFFFFF", "3", "C", "3", 128)
     chkPowMod(chk, "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "3", "C", "3", 128)
 
-#static:
-  #testModArith(ctCheck, ctTest)
+static:
+  testModArith(ctCheck, ctTest)
 
 suite "Wider unsigned Modular arithmetic coverage":
   testModArith(check, test)