[fuse-emulator-cvs] [fuse] branch master updated: Speed up readbyte()

[<fr...@us...>]

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fredm pushed a commit to branch master
in repository fuse.

View the commit online:
https://sourceforge.net/p/fuse-emulator/fuse/ci/fe8398c068b951b4b3a4672eca19d888ca1c4397/

The following commit(s) were added to refs/heads/master by this push:
     new fe8398c0 Speed up readbyte()
fe8398c0 is described below

commit fe8398c068b951b4b3a4672eca19d888ca1c4397
Author: Jindřich Makovička <mak...@gm...>
AuthorDate: Sat Mar 20 13:55:04 2021 +1100

    Speed up readbyte()
    
    Check the address first and only test for the peripherals if the address
    is in the relevant range.
---
 ChangeLog      |  3 +++
 memory_pages.c | 26 ++++++++++++++------------
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b13c8570..b8a1a8b8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,9 @@
 
         * Fuse 1.?.? released.
 
+        * Emulation core improvements:
+          * Speed up reading emulated memory locations (Jindřich Makovička).
+
         * UI improvements:
          * Timex: don't abort if the Timex dock cartridge image is not
            found (Alberto Garcia).
diff --git a/memory_pages.c b/memory_pages.c
index ddc79a32..c7543627 100644
--- a/memory_pages.c
+++ b/memory_pages.c
@@ -385,19 +385,21 @@ readbyte( libspectrum_word address )
   if( mapping->contended ) tstates += ula_contention[ tstates ];
   tstates += 3;
 
-  if( opus_active && address >= 0x2800 && address < 0x3800 )
-    return opus_read( address );
+  if( address < 0x4000 ) {
+    if( opus_active && address >= 0x2800 && address < 0x3800 )
+      return opus_read( address );
+
+    if( spectranet_paged ) {
+      if( spectranet_w5100_paged_a && address >= 0x1000 && address < 0x2000 )
+        return spectranet_w5100_read( mapping, address );
+      if( spectranet_w5100_paged_b && address >= 0x2000 && address < 0x3000 )
+        return spectranet_w5100_read( mapping, address );
+    }
 
-  if( spectranet_paged ) {
-    if( spectranet_w5100_paged_a && address >= 0x1000 && address < 0x2000 )
-      return spectranet_w5100_read( mapping, address );
-    if( spectranet_w5100_paged_b && address >= 0x2000 && address < 0x3000 )
-      return spectranet_w5100_read( mapping, address );
-  }
-  
-  if( ttx2000s_paged ) {
-    if( address >= 0x2000 && address < 0x4000 )
-      return ttx2000s_sram_read( address );
+    if( ttx2000s_paged ) {
+      if( address >= 0x2000 && address < 0x4000 )
+        return ttx2000s_sram_read( address );
+    }
   }
 
   return mapping->page[ address & MEMORY_PAGE_SIZE_MASK ];