Initial (manual) import

2017-01-22 20:26:44 +01:00
1 parent f39611c506
commit 895fe109de
@@ -0,0 +1,173 @@
+/*"Fixed point" means you use ints
+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 $TX,"faster",HTML="http://en.wikipedia.org/wiki/X87"$,
+but modern processors do well with
+floats.  It also depends on the compiler
+and my compiler is poor with floats.
+
+I often use 64-bit ints with upper 32-bits
+as int and lower 32-bits as fraction.
+
+See $LK,"::/Demo/SubIntAccess.HC"$ for how
+to access upper or lower 32-bits.
+*/
+
+#define SAMPLE_SIZE	10000000
+
+I32 coordinates[65536];
+
+asm {
+_ASM_FIXED_POINT::
+	PUSH	RBP
+	MOV	RBP,RSP
+	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
+	POP	RBP
+	RET
+
+SINE_VAL:	DU64	Sin(1.0);
+RET_VAL:	DU64	0;
+
+_ASM_FLOAT::
+	PUSH	RBP
+	MOV	RBP,RSP
+	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
+	POP	RBP
+	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,tmp,reg d2,reg sum;
+
+  CPURep;
+
+  //Set-up some sample coordinates
+  for (i=0;i<65536;i++)
+    coordinates[i]=RandU32;
+
+    //Measure Loop Overhead
+  start=GetTSC;
+  for (i=SAMPLE_SIZE-1;i>=0;i--) {
+  }
+  end=GetTSC;
+  overhead_time=end-start;
+  "$$RED$$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=GetTSC;
+  for (i=SAMPLE_SIZE-1;i>=0;i--)
+    fsum+=d1*coordinates[i&65535];
+  end=GetTSC;
+  test_time=end-start;
+  "Float Sum             :%X\n",ToI64(fsum);
+  "$$RED$$Float Cycles          :%10.5f$$FG$$\n",
+	ToF64(test_time)/SAMPLE_SIZE;
+
+  //Measure fixed point arithmetic
+  d2=Sin(1.0)*0x100000000;
+  sum=0;
+  start=GetTSC;
+  for (i=SAMPLE_SIZE-1;i>=0;i--) {
+    tmp=d2*coordinates[i&65535];
+    sum+=tmp.i32[1];
+  }
+  end=GetTSC;
+  test_time=end-start;
+  "Fixed-Point Sum       :%X\n",sum;
+  "$$RED$$Fixed-Point Cycles    :%10.5f$$FG$$\n",
+	ToF64(test_time)/SAMPLE_SIZE;
+
+  //Measure fixed point arithmetic
+  start=GetTSC;
+  sum=AsmFixedPt;
+  end=GetTSC;
+  test_time=end-start;
+  "Asm Fixed-Point Sum   :%X\n",sum;
+  "$$RED$$Asm Fixed-Point Cycles:%10.5f$$FG$$\n",
+	ToF64(test_time)/SAMPLE_SIZE;
+
+  //Measure float arithmetic
+  start=GetTSC;
+  sum=AsmFloat;
+  end=GetTSC;
+  test_time=end-start;
+  "Asm Float Sum         :%X\n",sum;
+  "$$RED$$Asm Float Cycles      :%10.5f$$FG$$\n",
+	ToF64(test_time)/SAMPLE_SIZE;
+
+}
+
+Main;
+
+/*  Program Output$HL,0$$WW+H,1$$FD,1$
+
+Machine 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$FG$
+
+Machine 2:
+8 Cores 3.395GHz
+$FG,4$Overhead Cycles       :   4.87040$FG$
+Float Sum             :D20A01DB177
+$FG,4$Float Cycles          :  10.11558$FG$
+Fixed-Point Sum       :D209FD18CC7
+$FG,4$Fixed-Point Cycles    :   4.50618$FG$
+Asm Fixed-Point Sum   :D209FD18CC7
+$FG,4$Asm Fixed-Point Cycles:   3.02426$FG$
+Asm Float Sum         :D20A01DB17B
+$FG,4$Asm Float Cycles      :   3.21070$FG$
+
+$HL,1$*/