From 11118be71770cefc3bf971798ac610dd2b4df807 Mon Sep 17 00:00:00 2001
From: Dylan Fei <feidylan23@gmail.com>
Date: Tue, 23 Dec 2025 15:54:35 +0800
Subject: [PATCH] Fix pointer difference issue in aarch64/riscv64

When calculating the difference between two pointers (TOK_PDIV), the
AArch64 and RISC-V64 backends used unsigned division
instructions (udiv/divu).

This patch moves TOK_PDIV to use signed division instructions (sdiv/div)
for both backends, ensuring correct behavior as per the C standard.
---
 arm64-gen.c   | 2 +-
 riscv64-gen.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arm64-gen.c b/arm64-gen.c
index 01ea3909..2038aeba 100644
--- a/arm64-gen.c
+++ b/arm64-gen.c
@@ -1756,6 +1756,7 @@ static void arm64_gen_opil(int op, uint32_t l)
         o(0x4b000000 | l << 31 | x | a << 5 | b << 16); // sub
         break;
     case '/':
+    case TOK_PDIV:
         o(0x1ac00c00 | l << 31 | x | a << 5 | b << 16); // sdiv
         break;
     case '^':
@@ -1798,7 +1799,6 @@ static void arm64_gen_opil(int op, uint32_t l)
         o(0x1ac02400 | l << 31 | x | a << 5 | b << 16); // lsr
         break;
     case TOK_UDIV:
-    case TOK_PDIV:
         o(0x1ac00800 | l << 31 | x | a << 5 | b << 16); // udiv
         break;
     case TOK_UGE:
diff --git a/riscv64-gen.c b/riscv64-gen.c
index e03d6e42..19c76682 100644
--- a/riscv64-gen.c
+++ b/riscv64-gen.c
@@ -1110,6 +1110,7 @@ static void gen_opil(int op, int ll)
         ER(0x33 | ll, 0, d, a, b, 1); // mul d, a, b
         break;
     case '/':
+    case TOK_PDIV:
         ER(0x33 | ll, 4, d, a, b, 1); // div d, a, b
         break;
     case '&':
@@ -1127,7 +1128,6 @@ static void gen_opil(int op, int ll)
     case TOK_UMOD:
         ER(0x33 | ll, 7, d, a, b, 1); // remu d, a, b
         break;
-    case TOK_PDIV:
     case TOK_UDIV:
         ER(0x33 | ll, 5, d, a, b, 1); // divu d, a, b
         break;