[ARM PATCH] 1300/1: more efficient irq number retrieval for PXA due to ARMv5 instructions

Patch from Nicolas Pitre

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 82293c58dfa20f780199fb1b000ca2a6bca7def2..33cf0ca2b347925930a4556c4d21de78f86a8029 100644 (file)
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -594,23 +594,12 @@ ENTRY(anakin_active_irqs)
                add     \base, \base, #0x00d00000
                ldr     \irqstat, [\base, #0]           @ ICIP
                ldr     \irqnr, [\base, #4]             @ ICMR
-               ands    \irqstat, \irqstat, \irqnr
-               mov     \irqnr, #0
+               ands    \irqnr, \irqstat, \irqnr
                beq     1001f
-               tst     \irqstat, #0xff00
-               moveq   \irqstat, \irqstat, lsr #8
-               addeq   \irqnr, \irqnr, #8
-               tsteq   \irqstat, #0xff00
-               moveq   \irqstat, \irqstat, lsr #8
-               addeq   \irqnr, \irqnr, #8
-               tst     \irqstat, #0x0f00
-               moveq   \irqstat, \irqstat, lsr #4
-               addeq   \irqnr, \irqnr, #4
-               tst     \irqstat, #0x0300
-               moveq   \irqstat, \irqstat, lsr #2
-               addeq   \irqnr, \irqnr, #2
-               tst     \irqstat, #0x0100
-               addeqs  \irqnr, \irqnr, #1
+               rsb     \irqstat, \irqnr, #0
+               and     \irqstat, \irqstat, \irqnr
+               clz     \irqnr, \irqstat
+               rsb     \irqnr, \irqnr, #23
 1001:
                .endm