TempleOSTS_130315.ISO

2018-09-08 21:45:37 +02:00
1 parent e57428affb
commit 17b71f1a2d
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+/*
+"Fixed point" means you use integers
+that are scaled by a value.  A common
+example would be using number of pennies
+instead of dollars with a float.
+
+Fixed-point used to be much faster,
+but modern processors do well with
+floats.  It also depends on the compiler
+and my compiler used to do floats poorly.
+
+I often use 64-bit ints with upper 32-bits
+as integer and lower 32-bits as fraction.
+
+See $LK-A,"::/TempleOS/Demo/SubIntAccess.CPP"$ for how
+to access upper or lower 32-bits.
+
+*/
+#define SAMPLE_SIZE	10000000
+
+I32 coordinates[65536];
+
+asm {
+	IMPORT coordinates;
+
+_ASM_FIXED_POINT::
+	ENTER	0
+	PUSH	RSI
+	PUSH	RDI
+	MOV	RSI,coordinates
+	MOV	RDI,ToI64(Sin(1.0)*0x100000000)
+	XOR	RBX,RBX	//SUM
+	MOV	RCX,SAMPLE_SIZE-1
+@@05:	XOR	RDX,RDX
+	MOV	DX,CX
+	MOVSXD	RAX,U32 [RSI+RDX*4]
+	IMUL	RDI
+	SAR	RAX,32
+	ADD	RBX,RAX
+	DEC	RCX
+	JGE	@@05
+	MOV	RAX,RBX
+	POP	RDI
+	POP	RSI
+	LEAVE
+	RET
+
+SINE_VAL:	DU64	Sin(1.0);
+RET_VAL:	DU64	0;
+
+_ASM_FLOAT::
+	ENTER	0
+	PUSH	RSI
+	MOV	RSI,coordinates
+	FLD	U64 [SINE_VAL]
+	FLDZ
+	MOV	RCX,SAMPLE_SIZE-1
+@@05:	XOR	RDX,RDX
+	MOV	DX,CX
+	FILD	U32 [RSI+RDX*4]
+	FMUL	ST0,ST2
+	FADDP	ST1,ST0
+	DEC	RCX
+	JGE	@@05
+	FISTP	U64 [RET_VAL]
+	MOV	RAX,U64 [RET_VAL]
+	FFREE	ST0
+	FINCSTP
+	POP	RSI
+	LEAVE
+	RET
+}
+
+_extern _ASM_FIXED_POINT I64 AsmFixedPt();
+_extern _ASM_FLOAT I64 AsmFloat();
+
+U0 Main()
+{
+  I64 start,end,overhead_time,test_time;
+  F64 d1,fsum;
+  I64 reg i,temp,reg d2,reg sum;
+  Bool old_preempt=Preempt(OFF);
+
+  CPURep;
+
+  //Set-up some sample coordinates
+  for (i=0;i<65536;i++)
+    coordinates[i]=RandU32;
+
+//Measure Loop Overhead
+  start=GetTimeStamp;
+  for (i=SAMPLE_SIZE-1;i>=0;i--) {
+  }
+  end=GetTimeStamp;
+  overhead_time=end-start;
+  "$$FG,RED$$Overhead Cycles       :%10.5f$$FG$$\n",
+    ToF64(overhead_time)/SAMPLE_SIZE;
+
+//Measure F64 arithmetic
+// (Some of this is due to crappy
+// compiler code.)
+  d1=Sin(1.0);
+  fsum=0;
+  start=GetTimeStamp;
+  for (i=SAMPLE_SIZE-1;i>=0;i--)
+    fsum+=d1*coordinates[i&65535];
+  end=GetTimeStamp;
+  test_time=end-start;
+  "Float Sum             :%X\n",ToI64(fsum);
+  "$$FG,RED$$Float Cycles          :%10.5f$$FG$$\n",
+    ToF64(test_time)/SAMPLE_SIZE;
+
+
+//Measure fixed point arithmetic
+  d2=Sin(1.0)*0x100000000;
+  sum=0;
+  start=GetTimeStamp;
+  for (i=SAMPLE_SIZE-1;i>=0;i--) {
+	  temp=d2*coordinates[i&65535];
+    sum+=temp.i32[1];
+  }
+  end=GetTimeStamp;
+  test_time=end-start;
+  "Fixed Point Sum       :%X\n",sum;
+  "$$FG,RED$$Fixed Point Cycles    :%10.5f$$FG$$\n",
+    ToF64(test_time)/SAMPLE_SIZE;
+
+//Measure fixed point arithmetic
+  start=GetTimeStamp;
+  sum=AsmFixedPt;
+  end=GetTimeStamp;
+  test_time=end-start;
+  "Asm Fixed Point Sum   :%X\n",sum;
+  "$$FG,RED$$Asm Fixed Point Cycles:%10.5f$$FG$$\n",
+    ToF64(test_time)/SAMPLE_SIZE;
+
+//Measure float arithmetic
+  start=GetTimeStamp;
+  sum=AsmFloat;
+  end=GetTimeStamp;
+  test_time=end-start;
+  "Asm Float Sum         :%X\n",sum;
+  "$$FG,RED$$Asm Float Cycles      :%10.5f$$FG$$\n",
+    ToF64(test_time)/SAMPLE_SIZE;
+
+  Preempt(old_preempt);
+}
+
+Main;
+
+/*  Program Output$HL,0$$WW+H,1$$FD,1$
+
+8 Cores 2.660GHz
+$FG,4$Overhead Cycles       :   2.00814$FG$
+Float Sum             :FFFFE1D361BEED68
+$FG,4$Float Cycles          :  10.16076$FG$
+Fixed Point Sum       :FFFFE1D361729914
+$FG,4$Fixed Point Cycles    :   5.29392$FG$
+Asm Fixed Point Sum   :FFFFE1D361729914
+$FG,4$Asm Fixed Point Cycles:   4.20464$FG$
+Asm Float Sum         :FFFFE1D361BEED56
+$FG,4$Asm Float Cycles      :   3.04635$FG$
+
+$HL,1$*/