[PATCH v3 2/5] hw/intc/loongarch_pch_pic: Fix bugs for update_irq function

[Xiaojuan Yang]

Fix such errors:
1. We should not use 'unsigned long' type as argument when we use
find_first_bit(), and we use ctz64() to replace find_first_bit()
to fix this bug.
2. It is not standard to use '1ULL << irq' to generate a irq mask.
So, we replace it with 'MAKE_64BIT_MASK(irq, 1)'.

Fix coverity CID: 1489761 1489764 1489765

Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
---
 hw/intc/loongarch_pch_pic.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/hw/intc/loongarch_pch_pic.c b/hw/intc/loongarch_pch_pic.c
index 3c9814a3b4..8fa64d2030 100644
--- a/hw/intc/loongarch_pch_pic.c
+++ b/hw/intc/loongarch_pch_pic.c
@@ -15,22 +15,26 @@
 
 static void pch_pic_update_irq(LoongArchPCHPIC *s, uint64_t mask, int level)
 {
-    unsigned long val;
+    uint64_t val;
     int irq;
 
     if (level) {
         val = mask & s->intirr & ~s->int_mask;
         if (val) {
-            irq = find_first_bit(&val, 64);
-            s->intisr |= 0x1ULL << irq;
-            qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 1);
+            irq = ctz64(val);
+            if (irq < 64) {
+                s->intisr |= MAKE_64BIT_MASK(irq, 1);
+                qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 1);
+            }
         }
     } else {
         val = mask & s->intisr;
         if (val) {
-            irq = find_first_bit(&val, 64);
-            s->intisr &= ~(0x1ULL << irq);
-            qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 0);
+            irq = ctz64(val);
+            if (irq < 64) {
+                s->intisr &= ~(MAKE_64BIT_MASK(irq, 1));
+                qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 0);
+            }
         }
     }
 }
-- 
2.31.1