diff --git a/klib/src/div.S b/am/src/mycpu/libgcc/div.S
similarity index 100%
rename from klib/src/div.S
rename to am/src/mycpu/libgcc/div.S
diff --git a/klib/src/muldi3.S b/am/src/mycpu/libgcc/muldi3.S
similarity index 100%
rename from klib/src/muldi3.S
rename to am/src/mycpu/libgcc/muldi3.S
diff --git a/klib/Makefile b/klib/Makefile
index 068a023..b117c60 100644
--- a/klib/Makefile
+++ b/klib/Makefile
@@ -1,4 +1,3 @@
 NAME = klib
 SRCS = $(shell find src/ -name "*.c")
-SRCS += $(shell find src/ -name "*.S")
 include $(AM_HOME)/Makefile
diff --git a/klib/src/int64.c b/klib/src/int64.c
index 8ef6d18..51401f8 100644
--- a/klib/src/int64.c
+++ b/klib/src/int64.c
@@ -363,7 +363,273 @@ uint32_t __inline __builtin_clzll(uint64_t value) {
 
 #include <am.h>
 
+/* Returns: a / b */
 
+COMPILER_RT_ABI di_int
+__divdi3(di_int a, di_int b)
+{
+    const int bits_in_dword_m1 = (int)(sizeof(di_int) * CHAR_BIT) - 1;
+    di_int s_a = a >> bits_in_dword_m1;           /* s_a = a < 0 ? -1 : 0 */
+    di_int s_b = b >> bits_in_dword_m1;           /* s_b = b < 0 ? -1 : 0 */
+    a = (a ^ s_a) - s_a;                         /* negate if s_a == -1 */
+    b = (b ^ s_b) - s_b;                         /* negate if s_b == -1 */
+    s_a ^= s_b;                                  /*sign of quotient */
+    return (__udivmoddi4(a, b, (du_int*)0) ^ s_a) - s_a;  /* negate if s_a == -1 */
+}
+
+/* Returns: a / b, *rem = a % b  */
+
+COMPILER_RT_ABI di_int
+__divmoddi4(di_int a, di_int b, di_int* rem)
+{
+  di_int d = __divdi3(a,b);
+  *rem = a - (d*b);
+  return d;
+}
+
+/* Returns: a % b */
+
+COMPILER_RT_ABI di_int
+__moddi3(di_int a, di_int b)
+{
+    const int bits_in_dword_m1 = (int)(sizeof(di_int) * CHAR_BIT) - 1;
+    di_int s = b >> bits_in_dword_m1;  /* s = b < 0 ? -1 : 0 */
+    b = (b ^ s) - s;                   /* negate if s == -1 */
+    s = a >> bits_in_dword_m1;         /* s = a < 0 ? -1 : 0 */
+    a = (a ^ s) - s;                   /* negate if s == -1 */
+    du_int r;
+    __udivmoddi4(a, b, &r);
+    return ((di_int)r ^ s) - s;                /* negate if s == -1 */
+}
+
+/* Returns: a / b */
+
+COMPILER_RT_ABI du_int
+__udivdi3(du_int a, du_int b)
+{
+    return __udivmoddi4(a, b, 0);
+}
+
+
+COMPILER_RT_ABI du_int
+__udivmoddi4(du_int a, du_int b, du_int* rem)
+{
+    const unsigned n_uword_bits = sizeof(su_int) * CHAR_BIT;
+    const unsigned n_udword_bits = sizeof(du_int) * CHAR_BIT;
+    udwords n;
+    n.all = a;
+    udwords d;
+    d.all = b;
+    udwords q;
+    udwords r;
+    unsigned sr;
+    /* special cases, X is unknown, K != 0 */
+    if (n.s.high == 0)
+    {
+        if (d.s.high == 0)
+        {
+            /* 0 X
+             * ---
+             * 0 X
+             */
+            if (rem)
+                *rem = n.s.low % d.s.low;
+            return n.s.low / d.s.low;
+        }
+        /* 0 X
+         * ---
+         * K X
+         */
+        if (rem)
+            *rem = n.s.low;
+        return 0;
+    }
+    /* n.s.high != 0 */
+    if (d.s.low == 0)
+    {
+        if (d.s.high == 0)
+        {
+            /* K X
+             * ---
+             * 0 0
+             */
+            if (rem)
+                *rem = n.s.high % d.s.low;
+            return n.s.high / d.s.low;
+        }
+        /* d.s.high != 0 */
+        if (n.s.low == 0)
+        {
+            /* K 0
+             * ---
+             * K 0
+             */
+            if (rem)
+            {
+                r.s.high = n.s.high % d.s.high;
+                r.s.low = 0;
+                *rem = r.all;
+            }
+            return n.s.high / d.s.high;
+        }
+        /* K K
+         * ---
+         * K 0
+         */
+        if ((d.s.high & (d.s.high - 1)) == 0)     /* if d is a power of 2 */
+        {
+            if (rem)
+            {
+                r.s.low = n.s.low;
+                r.s.high = n.s.high & (d.s.high - 1);
+                *rem = r.all;
+            }
+            return n.s.high >> __builtin_ctz(d.s.high);
+        }
+        /* K K
+         * ---
+         * K 0
+         */
+        sr = __builtin_clz(d.s.high) - __builtin_clz(n.s.high);
+        /* 0 <= sr <= n_uword_bits - 2 or sr large */
+        if (sr > n_uword_bits - 2)
+        {
+           if (rem)
+                *rem = n.all;
+            return 0;
+        }
+        ++sr;
+        /* 1 <= sr <= n_uword_bits - 1 */
+        /* q.all = n.all << (n_udword_bits - sr); */
+        q.s.low = 0;
+        q.s.high = n.s.low << (n_uword_bits - sr);
+        /* r.all = n.all >> sr; */
+        r.s.high = n.s.high >> sr;
+        r.s.low = (n.s.high << (n_uword_bits - sr)) | (n.s.low >> sr);
+    }
+    else  /* d.s.low != 0 */
+    {
+        if (d.s.high == 0)
+        {
+            /* K X
+             * ---
+             * 0 K
+             */
+            if ((d.s.low & (d.s.low - 1)) == 0)     /* if d is a power of 2 */
+            {
+                if (rem)
+                    *rem = n.s.low & (d.s.low - 1);
+                if (d.s.low == 1)
+                    return n.all;
+                sr = __builtin_ctz(d.s.low);
+                q.s.high = n.s.high >> sr;
+                q.s.low = (n.s.high << (n_uword_bits - sr)) | (n.s.low >> sr);
+                return q.all;
+            }
+            /* K X
+             * ---
+             * 0 K
+             */
+            sr = 1 + n_uword_bits + __builtin_clz(d.s.low) - __builtin_clz(n.s.high);
+            /* 2 <= sr <= n_udword_bits - 1
+             * q.all = n.all << (n_udword_bits - sr);
+             * r.all = n.all >> sr;
+             */
+            if (sr == n_uword_bits)
+            {
+                q.s.low = 0;
+                q.s.high = n.s.low;
+                r.s.high = 0;
+                r.s.low = n.s.high;
+            }
+            else if (sr < n_uword_bits)  // 2 <= sr <= n_uword_bits - 1
+            {
+                q.s.low = 0;
+                q.s.high = n.s.low << (n_uword_bits - sr);
+                r.s.high = n.s.high >> sr;
+                r.s.low = (n.s.high << (n_uword_bits - sr)) | (n.s.low >> sr);
+            }
+            else              // n_uword_bits + 1 <= sr <= n_udword_bits - 1
+            {
+                q.s.low = n.s.low << (n_udword_bits - sr);
+                q.s.high = (n.s.high << (n_udword_bits - sr)) |
+                           (n.s.low >> (sr - n_uword_bits));
+                r.s.high = 0;
+                r.s.low = n.s.high >> (sr - n_uword_bits);
+            }
+        }
+        else
+        {
+            /* K X
+             * ---
+             * K K
+             */
+            sr = __builtin_clz(d.s.high) - __builtin_clz(n.s.high);
+            /* 0 <= sr <= n_uword_bits - 1 or sr large */
+            if (sr > n_uword_bits - 1)
+            {
+                if (rem)
+                    *rem = n.all;
+                return 0;
+            }
+            ++sr;
+            /* 1 <= sr <= n_uword_bits */
+            /*  q.all = n.all << (n_udword_bits - sr); */
+            q.s.low = 0;
+            if (sr == n_uword_bits)
+            {
+                q.s.high = n.s.low;
+                r.s.high = 0;
+                r.s.low = n.s.high;
+            }
+            else
+            {
+                q.s.high = n.s.low << (n_uword_bits - sr);
+                r.s.high = n.s.high >> sr;
+                r.s.low = (n.s.high << (n_uword_bits - sr)) | (n.s.low >> sr);
+            }
+        }
+    }
+    /* Not a special case
+     * q and r are initialized with:
+     * q.all = n.all << (n_udword_bits - sr);
+     * r.all = n.all >> sr;
+     * 1 <= sr <= n_udword_bits - 1
+     */
+    su_int carry = 0;
+    for (; sr > 0; --sr)
+    {
+        /* r:q = ((r:q)  << 1) | carry */
+        r.s.high = (r.s.high << 1) | (r.s.low  >> (n_uword_bits - 1));
+        r.s.low  = (r.s.low  << 1) | (q.s.high >> (n_uword_bits - 1));
+        q.s.high = (q.s.high << 1) | (q.s.low  >> (n_uword_bits - 1));
+        q.s.low  = (q.s.low  << 1) | carry;
+        /* carry = 0;
+         * if (r.all >= d.all)
+         * {
+         *      r.all -= d.all;
+         *      carry = 1;
+         * }
+         */
+        const di_int s = (di_int)(d.all - r.all - 1) >> (n_udword_bits - 1);
+        carry = s & 1;
+        r.all -= d.all & s;
+    }
+    q.all = (q.all << 1) | carry;
+    if (rem)
+        *rem = r.all;
+    return q.all;
+}
+
+/* Returns: a % b */
+
+COMPILER_RT_ABI du_int
+__umoddi3(du_int a, du_int b)
+{
+    du_int r;
+    __udivmoddi4(a, b, &r);
+    return r;
+}
 
 // Returns: the number of leading 0-bits
 
diff --git a/scripts/riscv64-mycpu.mk b/scripts/riscv64-mycpu.mk
index 8da161b..2a0780d 100644
--- a/scripts/riscv64-mycpu.mk
+++ b/scripts/riscv64-mycpu.mk
@@ -6,6 +6,8 @@ LDFLAGS       += -melf64lriscv
 
 AM_SRCS := mycpu/start.S \
            mycpu/trm.c \
+           mycpu/libgcc/muldi3.S \
+           mycpu/libgcc/div.S \
            mycpu/ioe.c \
            mycpu/timer.c \
            mycpu/input.c