diff --git a/liba/Makefile b/liba/Makefile
index 0abd5ac52..933398b00 100644
--- a/liba/Makefile
+++ b/liba/Makefile
@@ -67,6 +67,7 @@ liba/src/external/openbsd/s_roundf.o: CFLAGS += -Os
 endif
 
 tests += $(addprefix liba/test/, \
+  aeabi.c \
   ieee754.c \
   stdint.c \
   strlcpy.c \
diff --git a/liba/src/aeabi-rt/llsl.c b/liba/src/aeabi-rt/llsl.c
index 1a510f689..85b6b0d0c 100644
--- a/liba/src/aeabi-rt/llsl.c
+++ b/liba/src/aeabi-rt/llsl.c
@@ -1,9 +1,14 @@
 /* See the "Run-time ABI for the ARM Architecture", Section 4.2 */
 
-typedef int uint32_t;
+typedef unsigned int uint32_t;
 
 long long __aeabi_llsl(long long value, int shift) {
   uint32_t low = (uint32_t)value << shift;
-  uint32_t high = ((uint32_t)(value >> 32) << shift) | ((uint32_t)value >> (32 - shift));
+  uint32_t high = ((uint32_t)(value >> 32) << shift);
+  if (shift < 32) {
+    high |= ((uint32_t)value >> (32 - shift));
+  } else {
+    high |= ((uint32_t)value << (shift - 32));
+  }
   return ((long long)high << 32) | low;
 }
diff --git a/liba/src/aeabi-rt/llsr.c b/liba/src/aeabi-rt/llsr.c
index 81c76075a..38c200cce 100644
--- a/liba/src/aeabi-rt/llsr.c
+++ b/liba/src/aeabi-rt/llsr.c
@@ -1,9 +1,14 @@
 /* See the "Run-time ABI for the ARM Architecture", Section 4.2 */
 
-typedef int uint32_t;
+typedef unsigned int uint32_t;
 
 long long __aeabi_llsr(long long value, int shift) {
-  uint32_t low = ((uint32_t)value >> shift) | ((uint32_t)(value >> 32) << (32 - shift));
-  uint32_t high = (uint32_t)value >> shift;
+  uint32_t low = ((uint32_t)value >> shift);
+  if (shift < 32) {
+    low |= ((uint32_t)(value >> 32) << (32 - shift));
+  } else {
+    low |= ((uint32_t)(value >> 32) >> (shift - 32));
+  }
+  uint32_t high = (uint32_t)(value >> 32) >> shift;
   return ((long long)high << 32) | low;
 }
diff --git a/liba/test/aeabi.c b/liba/test/aeabi.c
new file mode 100644
index 000000000..d4fc48aa3
--- /dev/null
+++ b/liba/test/aeabi.c
@@ -0,0 +1,42 @@
+#include <quiz.h>
+#include <stdint.h>
+#include <assert.h>
+
+long long __aeabi_llsl(long long value, int shift);
+long long __aeabi_llsr(long long value, int shift);
+
+QUIZ_CASE(liba_llsl) {
+  assert(__aeabi_llsl((uint64_t)1, 1) == (uint64_t)0x2);
+  assert(__aeabi_llsl((uint64_t)1, 2) == (uint64_t)0x4);
+  assert(__aeabi_llsl((uint64_t)1, 10) == (uint64_t)0x400);
+  assert(__aeabi_llsl((uint64_t)1, 20) == (uint64_t)0x100000);
+  assert(__aeabi_llsl((uint64_t)1, 30) == (uint64_t)0x40000000);
+  assert(__aeabi_llsl((uint64_t)1, 31) == (uint64_t)0x80000000);
+  assert(__aeabi_llsl((uint64_t)1, 32) == (uint64_t)0x100000000);
+  assert(__aeabi_llsl((uint64_t)1, 33) == (uint64_t)0x200000000);
+  assert(__aeabi_llsl((uint64_t)1, 40) == (uint64_t)0x10000000000);
+  assert(__aeabi_llsl((uint64_t)1, 50) == (uint64_t)0x4000000000000);
+  assert(__aeabi_llsl((uint64_t)1, 60) == (uint64_t)0x1000000000000000);
+  assert(__aeabi_llsl((uint64_t)1, 61) == (uint64_t)0x2000000000000000);
+  assert(__aeabi_llsl((uint64_t)1, 62) == (uint64_t)0x4000000000000000);
+  assert(__aeabi_llsl((uint64_t)1, 63) == (uint64_t)0x8000000000000000);
+  assert(__aeabi_llsl((uint64_t)1, 64) == (uint64_t)0);
+}
+
+QUIZ_CASE(liba_llsr) {
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 1) == (uint64_t)0x4000000000000000);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 2) == (uint64_t)0x2000000000000000);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 10) == (uint64_t)0x20000000000000);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 20) == (uint64_t)0x80000000000);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 30) == (uint64_t)0x200000000);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 31) == (uint64_t)0x100000000);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 32) == (uint64_t)0x80000000);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 33) == (uint64_t)0x40000000);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 40) == (uint64_t)0x800000);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 50) == (uint64_t)0x2000);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 60) == (uint64_t)0x8);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 61) == (uint64_t)0x4);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 62) == (uint64_t)0x2);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 63) == (uint64_t)0x1);
+  assert(__aeabi_llsr((uint64_t)0x8000000000000000, 64) == (uint64_t)0);
+}