From 7e65c2bdad5e5ee545b2f3136c9d1b48deee285f Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Thu, 11 May 2023 18:15:37 -0500
Subject: [PATCH] Fix #1130 - mod flipped for signed integers.

---
 src/core/inttypes.c  | 22 ++++++++++++++++++----
 test/suite0006.janet |  8 ++++++++
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/src/core/inttypes.c b/src/core/inttypes.c
index 364d9ea8..aa53293c 100644
--- a/src/core/inttypes.c
+++ b/src/core/inttypes.c
@@ -502,6 +502,18 @@ static Janet cfun_it_s64_mod(int32_t argc, Janet *argv) {
     return janet_wrap_abstract(box);
 }
 
+static Janet cfun_it_s64_modi(int32_t argc, Janet *argv) {
+    janet_fixarity(argc, 2);
+    int64_t *box = janet_abstract(&janet_s64_type, sizeof(int64_t));
+    int64_t op2 = janet_unwrap_s64(argv[0]);
+    int64_t op1 = janet_unwrap_s64(argv[1]);
+    int64_t x = op1 % op2;
+    *box = (op1 > 0)
+           ? ((op2 > 0) ? x : (0 == x ? x : x + op2))
+           : ((op2 > 0) ? (0 == x ? x : x + op2) : x);
+    return janet_wrap_abstract(box);
+}
+
 OPMETHOD(int64_t, s64, add, +)
 OPMETHOD(int64_t, s64, sub, -)
 OPMETHODINVERT(int64_t, s64, subi, -)
@@ -509,6 +521,7 @@ OPMETHOD(int64_t, s64, mul, *)
 DIVMETHOD_SIGNED(int64_t, s64, div, /)
 DIVMETHOD_SIGNED(int64_t, s64, rem, %)
 DIVMETHODINVERT_SIGNED(int64_t, s64, divi, /)
+DIVMETHODINVERT_SIGNED(int64_t, s64, remi, /)
 OPMETHOD(int64_t, s64, and, &)
 OPMETHOD(int64_t, s64, or, |)
 OPMETHOD(int64_t, s64, xor, ^)
@@ -521,6 +534,7 @@ OPMETHOD(uint64_t, u64, mul, *)
 DIVMETHOD(uint64_t, u64, div, /)
 DIVMETHOD(uint64_t, u64, mod, %)
 DIVMETHODINVERT(uint64_t, u64, divi, /)
+DIVMETHODINVERT(uint64_t, u64, modi, %)
 OPMETHOD(uint64_t, u64, and, &)
 OPMETHOD(uint64_t, u64, or, |)
 OPMETHOD(uint64_t, u64, xor, ^)
@@ -542,9 +556,9 @@ static JanetMethod it_s64_methods[] = {
     {"/", cfun_it_s64_div},
     {"r/", cfun_it_s64_divi},
     {"mod", cfun_it_s64_mod},
-    {"rmod", cfun_it_s64_mod},
+    {"rmod", cfun_it_s64_modi},
     {"%", cfun_it_s64_rem},
-    {"r%", cfun_it_s64_rem},
+    {"r%", cfun_it_s64_remi},
     {"&", cfun_it_s64_and},
     {"r&", cfun_it_s64_and},
     {"|", cfun_it_s64_or},
@@ -567,9 +581,9 @@ static JanetMethod it_u64_methods[] = {
     {"/", cfun_it_u64_div},
     {"r/", cfun_it_u64_divi},
     {"mod", cfun_it_u64_mod},
-    {"rmod", cfun_it_u64_mod},
+    {"rmod", cfun_it_u64_modi},
     {"%", cfun_it_u64_mod},
-    {"r%", cfun_it_u64_mod},
+    {"r%", cfun_it_u64_modi},
     {"&", cfun_it_u64_and},
     {"r&", cfun_it_u64_and},
     {"|", cfun_it_u64_or},
diff --git a/test/suite0006.janet b/test/suite0006.janet
index cc9683c9..1e8b7237 100644
--- a/test/suite0006.janet
+++ b/test/suite0006.janet
@@ -261,4 +261,12 @@
 (modcheck -10 3)
 (modcheck -10 -3)
 
+# Check for issue #1130
+(var d (int/s64 7))
+(mod 0 d)
+
+(var d (int/s64 7))
+(def result (seq [n :in (range -21 0)] (mod n d)))
+(assert (deep= result (map int/s64 @[0 1 2 3 4 5 6 0 1 2 3 4 5 6 0 1 2 3 4 5 6])) "issue #1130")
+
 (end-suite)