docs: update division typo in ISA.md (openvm-org#1726)

Resolves openvm-org#1680.

Author: stephenh-axiom-xyz

docs/specs/ISA.md

@@ -398,7 +398,7 @@ signed×unsigned multiplication respectively.
 
 DIV_RV32 and DIVU_RV32 perform signed and unsigned integer division of 32-bits by 32-bits. REM_RV32
 and REMU_RV32 provide the remainder of the corresponding division operation. Integer division is defined by
-`dividend = q * divisor + r` where `0 <= |r| < |divisor|` and either `sign(r) = sign(divisor)` or `r = 0`.
+`dividend = q * divisor + r` where `0 <= |r| < |divisor|` and either `sign(r) = sign(dividend)` or `r = 0`.
 
 Below `x[n:m]` denotes the bits from `n` to `m` inclusive of `x`.
 

extensions/rv32im/circuit/src/divrem/core.rs

@@ -30,7 +30,7 @@ use strum::IntoEnumIterator;
 #[repr(C)]
 #[derive(AlignedBorrow)]
 pub struct DivRemCoreCols<T, const NUM_LIMBS: usize, const LIMB_BITS: usize> {
-    // b = c * q + r for some 0 <= |r| < |c| and sign(r) = sign(b).
+    // b = c * q + r for some 0 <= |r| < |c| and sign(r) = sign(b) or r = 0.
     pub b: [T; NUM_LIMBS],
     pub c: [T; NUM_LIMBS],
     pub q: [T; NUM_LIMBS],