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Power   PROC    a:REAL4, b:REAL4

    LOCAL cw:WORD

    LOCAL cwtemp:WORD



    fstcw   [cw]            ; Save current control word

    mov     ax, [cw]

    or      ax, 0C00h       ; Set rounding control to chop

    mov     [cwtemp], ax

    fldcw   [cwtemp]



    ; c = exp(b*log(a));

    fld     [b]

    fld     [a]

    fyl2x               ; st(0) = b*(2 log(a))

    fld     st(0)       ; Duplicate log

    frndint             ; Round to integer. st(1) = b*(2 log(a)), st(0) = (int)(b*(2 log(a)))

    fld     st(1)       ; ...and duplicate log again

    fsubr               ; st(0) = (b*(2 log(a)) - b*((int)(2 log(a))) (fraction only)

    f2xm1               ; st(0) = 2^st(0) - 1 (2^x float portion)

    fld1                ; add 1 again (why did that bastard sub it? :)

    fadd

    fscale              ; Calc the 2^x integer portion, and multiply with 2^x float portion, to get complete 2^x (based on 2^i * 2^f = 2^(i+f))

    fstp    st(1)       ; Clean up stack (fscale doesn't pop the scale argument...)

    fldcw   [cw]        ; Restore control word

    

    ret

Power   ENDP