From 9e821b96a74cc668d0e0cea2dd86e5f8c1452831 Mon Sep 17 00:00:00 2001
From: "balhau@balhau.net" <balhau@balhau.net>
Date: Sun, 26 Dec 2021 13:55:10 +0000
Subject: [PATCH] Refactor on premake5 more on types

* Refactor platform/types.hpp, added some support for x86 32bit types
* Refactor platform/platform.hpp, add #ifdef conditionals to detect x86,
32bit and 64bit arch
* Implement 32bit and 64bit getTimestamp based in assembly rdtsc. For
32bit a struct composed by two 32bit numbers was devised to represent a
ULong data type of 64bits
---
 app/clock.cpp             | 13 ++++++++++++
 app/volatile.cpp          | 22 --------------------
 premake/clock.lua         | 22 ++++++++++++++++++++
 premake5.lua              |  3 ++-
 src/cpu/x86/clock.cpp     | 44 +++++++++++++++++++++++++++++++++++++++
 src/cpu/x86/clock.hpp     |  9 ++++++--
 src/platform/platform.hpp | 16 +++++++++-----
 src/platform/types.hpp    | 29 +++++++++++++++++++++++++-
 8 files changed, 127 insertions(+), 31 deletions(-)
 create mode 100644 app/clock.cpp
 delete mode 100644 app/volatile.cpp
 create mode 100644 premake/clock.lua
 create mode 100644 src/cpu/x86/clock.cpp

diff --git a/app/clock.cpp b/app/clock.cpp
new file mode 100644
index 0000000..fef4a38
--- /dev/null
+++ b/app/clock.cpp
@@ -0,0 +1,13 @@
+#include <iostream>
+#include "../src/cpu/x86/clock.hpp"
+
+int main(void){
+    cpu::Clock *clock = new cpu::X86Clock();
+    std::cout << "Hello 1 -- " << clock->getTimestamp() <<std::endl;
+    std::cout << "Hello 2 -- " << clock->getTimestamp() <<std::endl;
+
+    delete clock;
+
+    //std::cout << "Hello 3 -- " << getTimestamp() <<std::endl;
+    //std::cout << "Hello 4 -- " << getTimestamp() <<std::endl;
+}
\ No newline at end of file
diff --git a/app/volatile.cpp b/app/volatile.cpp
deleted file mode 100644
index ae3a549..0000000
--- a/app/volatile.cpp
+++ /dev/null
@@ -1,22 +0,0 @@
-#include <iostream>
-
-inline unsigned long getTimestamp(){
-    unsigned long hi,lo;
-    asm ("rdtsc": "=a" (lo), "=d" (hi) );
-    return ((unsigned long) lo ) | ((unsigned long) hi << 32);
-}
-
-inline unsigned long getTimestampVolatile(){
-    unsigned hi,lo;
-    asm volatile("rdtsc": "=a" (lo), "=d" (hi) );
-    return ((unsigned long) lo )| ((unsigned long) hi << 32);
-}
-
-int main(void){
-    unsigned long t1=getTimestamp();
-    unsigned long t2=getTimestamp();
-    std::cout << "Hello 1 -- " << t1 <<std::endl;
-    std::cout << "Hello 2 -- " << t2 <<std::endl;
-    //std::cout << "Hello 3 -- " << getTimestamp() <<std::endl;
-    //std::cout << "Hello 4 -- " << getTimestamp() <<std::endl;
-}
\ No newline at end of file
diff --git a/premake/clock.lua b/premake/clock.lua
new file mode 100644
index 0000000..37118d4
--- /dev/null
+++ b/premake/clock.lua
@@ -0,0 +1,22 @@
+project "clock"
+kind "ConsoleApp"
+language "c++"
+targetdir "../bin/%{cfg.buildcfg}"
+objdir "../obj"
+
+--files {"**.hpp","**.cpp"}
+files {
+    "../app/clock.cpp",
+    "../src/cpu/**.hpp",
+    "../src/cpu/**.cpp"
+}
+
+filter "configurations:Debug"
+  defines { "DEBUG" }
+  symbols "On"
+
+filter "configurations:Release"
+    defines { "NDEBUG" }
+    optimize "On"
+
+filter { "system:linux" }
\ No newline at end of file
diff --git a/premake5.lua b/premake5.lua
index 95a3155..20ba28d 100644
--- a/premake5.lua
+++ b/premake5.lua
@@ -4,4 +4,5 @@ workspace "CppLib"
 
     include("premake/sse.lua")
     include("premake/libbmath.lua")
-    include("premake/maths.lua")
\ No newline at end of file
+    include("premake/maths.lua")
+    include("premake/clock.lua")
\ No newline at end of file
diff --git a/src/cpu/x86/clock.cpp b/src/cpu/x86/clock.cpp
new file mode 100644
index 0000000..7f3fa7f
--- /dev/null
+++ b/src/cpu/x86/clock.cpp
@@ -0,0 +1,44 @@
+#include "clock.hpp"
+
+#ifdef ARCH_X86    // IF is x86 architecture
+
+    cpu::X86Clock::X86Clock(){
+    }
+    cpu::X86Clock::~X86Clock(){
+    }
+
+    #ifdef ARCH_X86_64 // If its 64bit
+    /**
+     * @brief Uses [RDTSC](https://www.felixcloutier.com/x86/rdtsc) assembly instruction to fetch
+     * the Time-Stamp Counter
+     * rdtsc -> will set edx and eax (32bit) registers with high
+     * and low order of a 64bit number. For 64bit arch the
+     * high order 32 bits of rax and rdx will be cleared
+     * this is why we need to recompose the 64bit number from
+     * the two 32bit numbers
+     *
+     * @return ULong
+     */
+    ULong cpu::X86Clock::getTimestamp()
+    {
+        UInt hi, lo;
+        asmv("rdtsc"
+            : "=a"(lo), "=d"(hi));
+        return ((unsigned long)lo) | ((unsigned long)hi << 32);
+    }
+    #endif
+
+    #ifdef ARCH_X86_32
+    ULong cpu::X86Clock::getTimestamp()
+    {
+        UInt hi, lo;
+        asmv("rdtsc"
+            : "=a"(lo), "=d"(hi));
+        return ULong{
+            high : hi,
+            low : lo
+        };
+    }
+    #endif
+
+#endif
\ No newline at end of file
diff --git a/src/cpu/x86/clock.hpp b/src/cpu/x86/clock.hpp
index c2fcec9..096617c 100644
--- a/src/cpu/x86/clock.hpp
+++ b/src/cpu/x86/clock.hpp
@@ -4,5 +4,10 @@
 
 namespace cpu
 {
-
-}
\ No newline at end of file
+    class X86Clock: public Clock{
+        public:
+            X86Clock();
+            ~X86Clock();
+            ULong getTimestamp();
+    };
+};
\ No newline at end of file
diff --git a/src/platform/platform.hpp b/src/platform/platform.hpp
index c3a7a38..0d0b084 100644
--- a/src/platform/platform.hpp
+++ b/src/platform/platform.hpp
@@ -9,13 +9,19 @@
 #define ARCH_X86
 #endif
 
-#ifdef __x64__
-#define ARCH_X86
-#endif
-
 #ifdef __x86_64__
 #define ARCH_X86
 #endif
 
-//Redefine asm volatile as asmv to make inline assembly less verbose
+#if defined(__x86_64__) || defined(__i386) || defined(__x64__)
+#define ARCH_X86
+#endif
+
+#if defined(__x86_64__) || defined(__x64__)
+#define ARCH_X86_64
+#elif defined(__i386) || defined(_M_IX86)
+#define ARCH_X86_32
+#endif
+
+// Redefine asm volatile as asmv to make inline assembly less verbose
 #define asmv asm volatile
\ No newline at end of file
diff --git a/src/platform/types.hpp b/src/platform/types.hpp
index 4d8ca14..5aa6d99 100644
--- a/src/platform/types.hpp
+++ b/src/platform/types.hpp
@@ -4,7 +4,7 @@
 /*
  * Types for x86 architectures
  */
-#ifdef ARCH_X86
+#ifdef ARCH_X86_64
     // Signed type alias
     typedef int Int;
     typedef long Long;
@@ -65,3 +65,30 @@
     #define SHIFT_8 8
 #endif
 
+#ifdef ARCH_X86_32
+    typedef int Int;
+    typedef char Char;
+    typedef short Short;
+
+    //64bit Long do not exist at cpu level
+    //emulate this via struct
+    typedef struct Long
+    {
+        Int high;
+        Int lo;
+    } Long;
+
+    // Unsigned type alias
+    typedef unsigned char UChar;
+    typedef unsigned short UShort;
+    typedef unsigned int UInt;
+    
+    //64bit unsigned long do not exist at cpu level
+    //emulate this via struct
+    typedef struct ULong {
+        UInt high;
+        UInt low;
+    } ULong;
+
+#endif
+