From 5dc4496b54422853cb785fb2dcb0fbada28627f1 Mon Sep 17 00:00:00 2001
From: Yen-Fu Chen <qwe661234@gmail.com>
Date: Fri, 7 Jun 2024 23:32:07 +0800
Subject: [PATCH] asd

---
 src/jit.c | 73 +++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 52 insertions(+), 21 deletions(-)

diff --git a/src/jit.c b/src/jit.c
index bdcdd0f1..adf97843 100644
--- a/src/jit.c
+++ b/src/jit.c
@@ -762,24 +762,6 @@ static inline void emit_alu64_imm32(struct jit_state *state,
     emit_alu64(state, op, src, dst);
     emit4(state, imm);
 }
-#elif defined(__aarch64__)
-static void divmod(struct jit_state *state,
-                   uint8_t opcode,
-                   int rd,
-                   int rn,
-                   int rm)
-{
-    bool mod = (opcode & JIT_ALU_OP_MASK) == (JIT_OP_MOD_IMM & JIT_ALU_OP_MASK);
-    bool is64 = (opcode & JIT_CLS_MASK) == JIT_CLS_ALU64;
-    int div_dest = mod ? temp_div_reg : rd;
-
-    /* Do not need to treet divide by zero as special because the UDIV
-     * instruction already returns 0 when dividing by zero.
-     */
-    emit_dataproc_2source(state, is64, DP2_UDIV, div_dest, rn, rm);
-    if (mod)
-        emit_dataproc_3source(state, is64, DP3_MSUB, rd, rm, div_dest, rn);
-}
 #endif
 
 static inline void emit_cmp_imm32(struct jit_state *state, int dst, int32_t imm)
@@ -1035,8 +1017,57 @@ static inline void emit_exit(struct jit_state *state)
 #endif
 }
 
-/* TODO: muldivmod is incomplete, it does not handle imm or overflow now */
 #if RV32_HAS(EXT_M)
+#if defined(__aarch64__)
+static void emit_conditional_move(struct jit_state *state,
+                                  int rd,
+                                  int rn,
+                                  int rm,
+                                  int cond)
+{
+    emit_a64(state, 0x1a800000 | (rm << 16) | (cond << 12) | (rn << 5) | rd);
+    set_dirty(rd, true);
+}
+
+static void divmod(struct jit_state *state,
+                   uint8_t opcode,
+                   int rd,
+                   int rn,
+                   int rm,
+                   bool sign)
+{
+    bool mod = (opcode & JIT_ALU_OP_MASK) == (JIT_OP_MOD_IMM & JIT_ALU_OP_MASK);
+    bool is64 = (opcode & JIT_CLS_MASK) == JIT_CLS_ALU64;
+    int div_dest = mod ? temp_div_reg : rd;
+    
+    if (sign) 
+        emit_cmp_imm32(state, rd, 0x80000000); /* overflow checking */
+
+    emit_dataproc_2source(state, is64, DP2_UDIV, div_dest, rn, rm);
+    if (mod)
+        emit_dataproc_3source(state, is64, DP3_MSUB, rd, rm, div_dest, rn);
+    
+    if (sign) {
+        /* handle overflow */
+        uint32_t jump_loc = state->offset;
+        emit_jcc_offset(state, 0x85);
+        emit_cmp_imm32(state, rm, -1);
+        if (mod)
+            emit_load_imm(state, R10, 0);
+        else
+            emit_load_imm(state, R10, 0x80000000);
+        emit_conditional_move(state, rd, R10, rd, COND_EQ);
+        emit_jump_target_offset(state, JUMP_LOC, state->offset);
+    }
+    if (!mod) {
+        /* handle dividing zero */
+        emit_cmp_imm32(state, rm, 0);
+        emit_load_imm(state, temp_reg, -1);
+        emit_conditional_move(state, rd, temp_reg, rd, COND_EQ);
+    }
+}
+#endif
+
 static void muldivmod(struct jit_state *state,
                       uint8_t opcode,
                       int src,
@@ -1190,10 +1221,10 @@ static void muldivmod(struct jit_state *state,
         emit_dataproc_3source(state, true, DP3_MADD, dst, dst, src, RZ);
         break;
     case 0x38:
-        divmod(state, JIT_OP_DIV_REG, dst, dst, src);
+        divmod(state, JIT_OP_DIV_REG, dst, dst, src, sign);
         break;
     case 0x98:
-        divmod(state, JIT_OP_MOD_REG, dst, dst, src);
+        divmod(state, JIT_OP_MOD_REG, dst, dst, src, sign);
         break;
     default:
         __UNREACHABLE;