kernel_if: reduce scope of variables

Declare `segment` as `unsigned int` to avoid unnecessary type punning.

Keep zeroing upper bits since `unsigned int` may be larger than 32 bits.

Author: pcolberg

src/acl_kernel_if.cpp

@@ -1288,17 +1288,8 @@ void acl_kernel_if_launch_kernel(acl_kernel_if *kern,
 // Called when we receive a kernel status interrupt.  Cycle through all of
 // the running accelerators and check for updated status.
 void acl_kernel_if_update_status(acl_kernel_if *kern) {
-  unsigned int k, i;
-  unsigned int csr;
-  int activation_id;
-  unsigned int printf_size;
-  uintptr_t segment, segment_pre_irq;
   acl_assert_locked_or_sig();
 
-#ifdef TEST_PROFILING_HARDWARE
-  uint64_t data[10];
-#endif
-
 #ifdef POLLING
   ACL_KERNEL_IF_DEBUG_MSG_VERBOSE(kern, 10, ":: Updating kernel status.\n");
 #else
@@ -1308,15 +1299,17 @@ void acl_kernel_if_update_status(acl_kernel_if *kern) {
   // Get the state of kernel_cra address span extender segment prior to IRQ in
   // hardware If IRQ is received in middle of segment change, segment value in
   // cache and hardware could go out of sync
-  acl_kernel_if_read_32b(kern, OFFSET_KERNEL_CRA_SEGMENT,
-                         (unsigned int *)&segment);
+  {
+    unsigned int segment;
+    acl_kernel_if_read_32b(kern, OFFSET_KERNEL_CRA_SEGMENT, &segment);
 
-  // Zero upper 32-bits on 64-bit machines
-  kern->cur_segment = segment & 0xffffffff;
-  segment_pre_irq = kern->cur_segment;
+    // Zero upper 32-bits on 64-bit machines
+    kern->cur_segment = segment & 0xffffffff;
+  }
+  const uintptr_t segment_pre_irq = kern->cur_segment;
 
   // Check which accelerators are done and update their status appropriately
-  for (k = 0; k < kern->num_accel; ++k) {
+  for (unsigned int k = 0; k < kern->num_accel; ++k) {
     int next_queue_back;
     unsigned int finish_counter = 0;
 
@@ -1335,7 +1328,7 @@ void acl_kernel_if_update_status(acl_kernel_if *kern) {
     }
 
     // Read the accelerator's status register
-    csr = 0;
+    unsigned int csr = 0;
     acl_kernel_cra_read(kern, k, KERNEL_OFFSET_CSR, &csr);
 
     // Ignore non-status bits.
@@ -1370,11 +1363,11 @@ void acl_kernel_if_update_status(acl_kernel_if *kern) {
         ACL_KERNEL_READ_BIT(csr, KERNEL_CSR_PROFILE_TEMPORAL_STATUS) == 0)
       continue;
 
-    activation_id = kern->accel_job_ids[k][next_queue_back];
+    int activation_id = kern->accel_job_ids[k][next_queue_back];
 
     // read the printf buffer size from the kernel cra, just after the
     // kernel arguments
-    printf_size = 0;
+    unsigned int printf_size = 0;
     if (kern->accel_num_printfs[k] > 0) {
       acl_kernel_cra_read(kern, k, KERNEL_OFFSET_PRINTF_BUFFER_SIZE,
                           &printf_size);
@@ -1451,7 +1444,7 @@ void acl_kernel_if_update_status(acl_kernel_if *kern) {
                               finish_counter);
     }
 
-    for (i = 0; i < finish_counter; i++) {
+    for (unsigned int i = 0; i < finish_counter; i++) {
       activation_id = kern->accel_job_ids[k][next_queue_back];
 
       // Tell the host library this job is done
@@ -1463,6 +1456,8 @@ void acl_kernel_if_update_status(acl_kernel_if *kern) {
       ACL_KERNEL_IF_DEBUG_MSG(
           kern, ":: testing profile hardware on accel_id=%u.\n", k);
 
+      uint64_t data[10];
+
       acl_hal_mmd_get_profile_data(kern->physical_device_id, k, data, 6);
 
       acl_hal_mmd_reset_profile_counters(kern->physical_device_id, k);