Texas Instruments TMS320C3x 사용자 설명서

Floating-Point Conversion (IEEE Std. 754)

 

5-24

Example 5–7. TMS320C3x-to-IEEE Conversion (Complete Version)

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TITLE TMS320C3x TO IEEE CONVERSION (COMPLETE VERSION)

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SUBROUTINE TOIEEE1

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FUNCTION: CONVERSION BETWEEN THE TMS320C3x FORMAT AND THE IEEE

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FLOATING-POINT FORMAT. THE NUMBER TO BE CONVERTED

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IS IN THE UPPER 32 BITS OF R0. THE RESULT WILL BE

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IN THE LOWER 32 BITS OF R0.

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UPON ENTERING THE ROUTINE, AR1 POINTS TO THE FOLLOWING TABLE:

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(0) 0xFF800000 <

– –

 AR1

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(1) 0xFF000000
(2) 0x7F000000

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(3) 0x80000000

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(4) 0x81000000

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(5) 0x7F800000

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(6) 0x00400000

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(7) 0x007FFFFF

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(8) 0x7F7FFFFF

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ARGUMENT

ASSIGNMENTS:

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ARGUMENT

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FUNCTION

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––––––––––+–––––––––––––––––––––––––––––––––––––

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R0

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NUMBER TO BE CONVERTED

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AR1

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POINTER TO TABLE WITH CONSTANTS

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REGISTERS USED AS INPUT: R0, AR1

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REGISTERS MODIFIED: R0

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REGISTER CONTAINING RESULT: R0

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NOTE:

SINCE THE STACK POINTER ’SP’ IS USED, MAKE SURE TO

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INITIALIZE IT IN THE CALLING PROGRAM.

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CYCLES: 31 (WORST CASE)

WORDS: 25

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.global

TOIEEE1