Texas Instruments TMS320C3x User Manual
Page 129
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 <
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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