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27 lines
688 B
27 lines
688 B
; convert a 32 bit integer into 64 bit double
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;
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.ppc
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.code
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align 4
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__itod proc public
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stwu sp,-8(sp)
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xoris r3,r3,8000h ;invert the sign bit
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addis r0,r0,4330h ;make a 2 to 52 exponent for the double
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stw r3,4(sp) ;store the int into the last four bytes of the double
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stw r0,0(sp) ;store the 2 to 52 exponent part for the double
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lwz r3,pdw(r2) ;load float format of number 2 to 52 with inverted sign bit too
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lfs fp0,0(r3) ;load float format into fp0
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lfd fp1,0(sp) ;load double format into fp1
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fsub fp1,fp1,fp0 ;substract fp0 from fp1, if r3 is negative, the result will be negative here
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addic sp,sp,8
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ret
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__itod endp
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.data
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pdw dd 059800004h
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end
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