From 20b3ca2e081e9ee076483ca06e382002709b54dd Mon Sep 17 00:00:00 2001
From: Inderpreet Singh <w6o6@ece.ubc.ca>
Date: Mon, 26 Dec 2011 00:07:19 -0800
Subject: Fix for Bug 124 - ld.local.s8 instructions are not supported

[git-p4: depot-paths = "//depot/gpgpu_sim_research/fermi/distribution/": change = 11231]
---
 src/abstract_hardware_model.cc | 16 +++++++++++++---
 src/gpgpu-sim/shader.cc        | 34 +++++++++++++++++++++++++---------
 2 files changed, 38 insertions(+), 12 deletions(-)

diff --git a/src/abstract_hardware_model.cc b/src/abstract_hardware_model.cc
index 19c3091..1a06001 100644
--- a/src/abstract_hardware_model.cc
+++ b/src/abstract_hardware_model.cc
@@ -313,9 +313,19 @@ void warp_inst_t::memory_coalescing_arch_13( bool is_write, mem_access_type acce
             if( !active(thread) )
                 continue;
 
-            // local memory can only be accessed in 4B chunks by one thread
-            unsigned data_size_coales = (space.get_type() == local_space || space.get_type() == param_space_local ) ? 4 : data_size;
-            unsigned num_accesses = (space.get_type() == local_space || space.get_type() == param_space_local ) ? data_size/4 : 1;
+            unsigned data_size_coales = data_size;
+            unsigned num_accesses = 1;
+
+            if( space.get_type() == local_space || space.get_type() == param_space_local ) {
+               // Local memory accesses >4B were split into 4B chunks
+               if(data_size >= 4) {
+                  data_size_coales = 4;
+                  num_accesses = data_size/4;
+               }
+               // Otherwise keep the same data_size for sub-4B access to local memory
+            }
+
+
             assert(num_accesses <= MAX_ACCESSES_PER_INSN_PER_THREAD);
 
             for(unsigned access=0; access<num_accesses; access++) {
diff --git a/src/gpgpu-sim/shader.cc b/src/gpgpu-sim/shader.cc
index 7ef5140..b513edb 100644
--- a/src/gpgpu-sim/shader.cc
+++ b/src/gpgpu-sim/shader.cc
@@ -795,16 +795,32 @@ unsigned shader_core_ctx::translate_local_memaddr( address_type localaddr, unsig
    }
    assert( thread_base < 4/*word size*/*max_concurrent_threads );
 
-   assert(datasize%4 == 0);
-   assert(datasize >= 4);
-   assert(datasize/4 <= MAX_ACCESSES_PER_INSN_PER_THREAD); // max 32B
-   assert(localaddr%4 == 0); // Required if accessing 4B per request, otherwise access will overflow into next thread's space
-   for(unsigned i=0; i<datasize/4; i++) {
-       address_type local_word = localaddr/4 + i;
-       address_type linear_address = local_word*max_concurrent_threads*4 + thread_base + LOCAL_GENERIC_START;
-       translated_addrs[i] = linear_address;
+   // If requested datasize > 4B, split into multiple 4B accesses
+   // otherwise do one sub-4 byte memory access
+   unsigned num_accesses = 0;
+
+   if(datasize >= 4) {
+      // >4B access, split into 4B chunks
+      assert(datasize%4 == 0);   // Must be a multiple of 4B
+      num_accesses = datasize/4;
+      assert(num_accesses <= MAX_ACCESSES_PER_INSN_PER_THREAD); // max 32B
+      assert(localaddr%4 == 0); // Address must be 4B aligned - required if accessing 4B per request, otherwise access will overflow into next thread's space
+      for(unsigned i=0; i<num_accesses; i++) {
+          address_type local_word = localaddr/4 + i;
+          address_type linear_address = local_word*max_concurrent_threads*4 + thread_base + LOCAL_GENERIC_START;
+          translated_addrs[i] = linear_address;
+      }
+   } else {
+      // Sub-4B access, do only one access
+      assert(datasize > 0);
+      num_accesses = 1;
+      address_type local_word = localaddr/4;
+      address_type local_word_offset = localaddr%4;
+      assert( (localaddr+datasize-1)/4  == local_word ); // Make sure access doesn't overflow into next 4B chunk
+      address_type linear_address = local_word*max_concurrent_threads*4 + local_word_offset + thread_base + LOCAL_GENERIC_START;
+      translated_addrs[0] = linear_address;
    }
-   return datasize/4;
+   return num_accesses;
 }
 
 /////////////////////////////////////////////////////////////////////////////////////////
-- 
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