Solved–Lab 9 Floating Point Math– Solution

Description

9.1  Assignment

 

If floating point hardware is available, it can be used to greatly accelerate non-integral mathematical operations. For this lab, you are to re-write the program from Lab 8, but this time you must use floating point instructions to perform your calculations.

 

9.2  Instructions

 

Re-write the program from Lab 8, but this time, use ARM VFP instructions to perform floating point mathematics. You can use printf and scanf for output and input of floating point values. The following example shows how to print floating point values.

 

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• fmt: asciz “%f\n”

 

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• .

 

• .

 

• .

 

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• @@ printf expects all floating point parameters to be passed

 

• @@ as IEEE double precision. If the second parameter to printf

 

10@@ is a float, then printf expects the 64-bit value to be

 

11@@ passed in two registers.  The choice of registers depends

 

12@@ on the stack pointer.

 

13@@ printf acts as if r0-r3 are part of the stack and requires

 

14@@ the 64-bit value to be aligned on an 8-byte boundary.  The

 

15@@ following lines print out the number in d0 by moving it to

 

16@@ the appropriate registers and calling printf.

 

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tst

sp,#4

@ check to see if stack is aligned

 

• vmovne r1, r2, d0@ move to r1,r2 if not aligned

 

• vmoveq r2, r3, d0@ move to r2,r3 if aligned

 

20	ldr	r0,=fmt	@ load pointer to format string
21	bl	printf

 

 

 

 

 

 

 

 

 

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30                                                                                                                                 LAB 9. FLOATING POINT MATH