Add long-missing arm-algo.S

src/util/arm-algo.S

@@ -0,0 +1,31 @@
+# r0: Destination
+# r1: Source
+# r2: Number of words to copy as halfwords
+.global _to16Bit
+_to16Bit:
+push {r4-r10}
+mov r8, r0
+mov r9, r1
+mov r10, r2
+.L0:
+tst r10, #7
+beq .L1
+ldr r0, [r9], #4
+strh r0, [r8], #2
+sub r10, #1
+b .L0
+.L1:
+ldmia r9!, {r0-r7}
+strh r0, [r8], #2
+strh r1, [r8], #2
+strh r2, [r8], #2
+strh r3, [r8], #2
+strh r4, [r8], #2
+strh r5, [r8], #2
+strh r6, [r8], #2
+strh r7, [r8], #2
+subs r10, #8
+bne .L1
+.L9:
+pop {r4-r10}
+bx lr