- fixed watcom build

[dosdemo] / README.md

diff --git a/README.md b/README.md
index 4804bd7..496d395 100644 (file)
--- a/README.md
+++ b/README.md
@@ -25,11 +25,62 @@ which will in turn start dosbox, which will execute the DOS binary! If the gods
 are slumbering in valhalla, just typing `dosbox demo.exe` should do the trick.
 
 
 are slumbering in valhalla, just typing `dosbox demo.exe` should do the trick.
 
 

-SDL backend
------------
-Run make to build (assuming make on your system is GNU make).
+Building and running with the SDL backend
+-----------------------------------------
+Run make to build (assuming make on your system is GNU make), or use the visual
+studio 2013 project on Windows.

 
 The SDL backend will scale the framebuffer up, by the factor specified in the
 `FBSCALE` environment variable. So run the demo as: `FBSCALE=3 ./demo` for
 a 3x scale factor, or just export the `FBSCALE` env var in the shell you are
 going to use for running the demo. The default scale factor is 2x.
 
 The SDL backend will scale the framebuffer up, by the factor specified in the
 `FBSCALE` environment variable. So run the demo as: `FBSCALE=3 ./demo` for
 a 3x scale factor, or just export the `FBSCALE` env var in the shell you are
 going to use for running the demo. The default scale factor is 2x.

+
+Datafiles
+---------
+The demo datafiles are in their own subversion repo. To checkout the data files
+run the following in the demo root directory:
+
+  svn co svn://mutantstargoat.com/datadirs/dosdemo data
+
+Random optimization details about the Pentium1 (p54c)
+-----------------------------------------------------
+Use cround64 (util.h) for float -> integer conversions, instead of casts.
+
+Performance measurement with RDTSC:
+    perf_start();
+    /* code under test */
+    perf_end(); /* result in perf_interval_count */
+
+Cache organization (L1): 8kb data / 8kb instruction
+128 sets of 2 cache lines, 32 bytes per cache line.
+
+Addresses which are multiples of 4096 fall in the same set and can only have
+two of them in cache at any time.
+
+U/V pipe pairing rules:
+ - both instructions must be simple
+ - no read-after-write or write-after-write reg dependencies
+ - no displacement AND immediate in either instruction
+ - instr. with prefixes (except 0x0f) can only run on U pipe.
+ - prefixes are treated as separate 1-byte instructions (except 0x0f).
+ - branches can be paired if they are the second instr. of the pair only.
+
+Simple instructions are:
+ - mov reg, reg/mem/imm
+ - mov mem, reg/imm
+ - alu reg, reg/mem/imm (alu: add/sub/cmp/and/or/xor)
+ - alu mem, reg/imm
+ - inc reg/mem
+ - dec reg/mem
+ - push reg/mem
+ - pop reg
+ - lea reg,mem
+ - jmp/call/jcc near
+ - nop
+ - test reg,reg/mem
+ - test acc,imm
+
+U-only pairable instructions:
+ - adc, sbb
+ - shr, sar, shl, sal with immediate
+ - ror, rol, rcr, rcl with immediate=1