1 files changed, 57 insertions, 0 deletions
diff --git a/examples/asmsum.py b/examples/asmsum.py
new file mode 100644
index 0000000000..07e71c7384
--- /dev/null
+++ b/examples/asmsum.py
@@ -0,0 +1,57 @@
+@micropython.asm_thumb
+def asm_sum_words(r0, r1):
+
+    # r0 = len
+    # r1 = ptr
+    # r2 = sum
+    # r3 = dummy
+    mov(r2, 0)
+
+    b(loop_entry)
+
+    label(loop1)
+    ldr(r3, [r1, 0])
+    add(r2, r2, r3)
+
+    add(r1, r1, 4)
+    sub(r0, r0, 1)
+
+    label(loop_entry)
+    cmp(r0, 0)
+    bgt(loop1)
+
+    mov(r0, r2)
+
+@micropython.asm_thumb
+def asm_sum_bytes(r0, r1):
+
+    # r0 = len
+    # r1 = ptr
+    # r2 = sum
+    # r3 = dummy
+    mov(r2, 0)
+
+    b(loop_entry)
+
+    label(loop1)
+    ldrb(r3, [r1, 0])
+    add(r2, r2, r3)
+
+    add(r1, r1, 1)
+    sub(r0, r0, 1)
+
+    label(loop_entry)
+    cmp(r0, 0)
+    bgt(loop1)
+
+    mov(r0, r2)
+
+import array
+
+b = array.array('l', (100, 200, 300, 400))
+n = asm_sum_words(len(b), b)
+print(b, n)
+
+b = array.array('b', (10, 20, 30, 40, 50, 60, 70, 80))
+n = asm_sum_bytes(len(b), b)
+print(b, n)