[tkreuzer] 67642: [CRT] Implement __rt_srsh

Author: tkreuzer
Date: Sun May 10 21:04:48 2015
New Revision: 67642

URL: http://svn.reactos.org/svn/reactos?rev=67642&view=rev
Log:
[CRT]
Implement __rt_srsh

Modified:
    trunk/reactos/lib/sdk/crt/math/arm/__rt_srsh.s

Modified: trunk/reactos/lib/sdk/crt/math/arm/__rt_srsh.s
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/lib/sdk/crt/math/arm/__rt_…
==============================================================================
--- trunk/reactos/lib/sdk/crt/math/arm/__rt_srsh.s	[iso-8859-1] (original)
+++ trunk/reactos/lib/sdk/crt/math/arm/__rt_srsh.s	[iso-8859-1] Sun May 10 21:04:48 2015
@@ -13,10 +13,66 @@
 
     TEXTAREA
 
+/*
+    __int64
+    __rt_srsh(
+        __int64 value,
+        uint32_t shift);
+
+    R0 = loword of value
+    R1 = hiword of value
+    R2 = shift
+
+*/
+
     LEAF_ENTRY __rt_srsh
 
-	__assertfail
-	bx	lr
+    /* r3 = 32 - r2 */
+    rsbs r3, r2, #32
+
+    /* Branch if minus (r2 > 32)  */
+    bmi __rt_srsh2
+
+    /* r0 = r0 >> r2 (logical shift!) */
+    lsr r0, r0, r2
+
+    /* r3 = r1 << r3 */
+    lsl r3, r1, r3
+
+    /* r0 |= r1 << (32 - r2) */
+    orr r0, r0, r3
+
+    /* r1 = r1 >> r2 (arithmetic shift!) */
+    asr r1, r1, r2
+
+    bx lr
+
+__rt_srsh2
+
+    /* Check if shift is > 64 */
+    cmp r2, 64
+    bhs __rt_srsh3
+
+    /* r3 = r2 - 32 */
+    sub r3, r2, #32
+
+    /* r0 = r1 >> r3 (arithmetic shift!) */
+    asr r0, r1, r3
+
+    /* r1 = r1 >> 32 (arithmetic shift!) */
+    asr r1, r1, #32
+
+    bx lr
+
+__rt_srsh3
+
+    /* r1 = r1 >> 32 (arithmetic shift!) */
+    asr r1, r1, #32
+
+    /* r0 = r1 */
+    mov r0, r1
+
+    bx lr
 
     LEAF_END __rt_srsh