Code: Select all
Procedure.f mbf2ieee(src.f)
Protected dest.f
;
;unsigned char *msbin = (unsigned char *)src4;
;unsigned char *ieee = (unsigned char *)dest4;
;unsigned char sign = 0x00;
;unsigned char ieee_exp = 0x00;
;int i;
;/* MS Binary Format */
;/* byte order => m3 | m2 | m1 | exponent */
;/* m1 is most significant byte => sbbb|bbbb */
;/* m3 is the least significant byte */
;/* m = mantissa byte */
;/* s = sign bit */
;/* b = bit */
;sign = msbin[2] & 0x80; /* 1000|0000b */
sign.b = PeekB(@src + 2) & $80
;/* IEEE Single Precision Float Format */
;/* m3 m2 m1 exponent */
;/* mmmm|mmmm mmmm|mmmm emmm|mmmm seee|eeee */
;/* s = sign bit */
;/* e = exponent bit */
;/* m = mantissa bit */
;For (i=0; i<4; i++) ieee[i] = 0;
;/* any msbin w/ exponent of zero = zero */
;If (msbin[3] == 0) Return 0;
If PeekB(@src + 3)=0
ProcedureReturn 0
EndIf
;ieee[3] |= sign;
PokeB(@dest + 3, sign)
;/* MBF is bias 128 And IEEE is bias 127. ALSO, MBF places */
;/* the decimal point before the assumed bit, While */
;/* IEEE places the decimal point after the assumed bit. */
;ieee_exp = msbin[3] - 2; /* actually, msbin[3]-1-128+127 */
exp.b = PeekB(@src + 3) - 2
;/* the first 7 bits of the exponent in ieee[3] */
;ieee[3] |= ieee_exp >> 1;
PokeB(@dest + 3, PeekB(@dest + 3) | ((exp>>1) & $7F) )
;/* the one remaining bit in first bin of ieee[2] */
;ieee[2] |= ieee_exp << 7;
PokeB(@dest + 2, PeekB(@dest + 2) | (exp<<7) )
;/* 0111|1111b : mask out the msbin sign bit */
;ieee[2] |= msbin[2] & 0x7f;
PokeB(@dest + 2, PeekB(@dest + 2) | (PeekB(@src + 2) & $7F) )
;ieee[1] = msbin[1];
PokeB(@dest+1, PeekB(@src+1))
;ieee[0] = msbin[0];
PokeB(@dest, PeekB(@src))
;Return 0;
ProcedureReturn dest
;
EndProcedure
Procedure.d dmbf2ieee(src.d)
Protected dest.d, msbin.d
;
;unsigned char msbin[8];
;unsigned char *ieee = (unsigned char *)dest8;
;unsigned char sign = 0x00;
;unsigned int ieee_exp = 0x0000;
;int i;
;/* A manipulatable copy of the msbin number */
;strncpy((char *)msbin,(char *)src8,8);
msbin = src
;/* MS Binary Format */
;/* byte order => m7 | m6 | m5 | m4 | m3 | m2 | m1 | exponent */
;/* m1 is most significant byte => smmm|mmmm */
;/* m7 is the least significant byte */
;/* m = mantissa byte */
;/* s = sign bit */
;/* b = bit */
; sign = msbin[6] & 0x80; /* 1000|0000b */
sign.b = PeekB(@msbin + 6) & $80
;/* IEEE Single Precision Float Format */
;/* byte 8 byte 7 byte 6 byte 5 byte 4 And so on */
;/* seee|eeee eeee|mmmm mmmm|mmmm mmmm|mmmm mmmm|mmmm ... */
;/* s = sign bit */
;/* e = exponent bit */
;/* m = mantissa bit */
; For (i=0; i<8; i++) ieee[i] = 0;
; /* any msbin w/ exponent of zero = zero */
; If (msbin[7] == 0) Return 0;
If PeekB(@msbin + 7) = 0
ProcedureReturn 0
EndIf
;ieee[7] |= sign;
PokeB(@dest+7, sign)
;/* MBF is bias 128 And IEEE is bias 1023. ALSO, MBF places */
;/* the decimal point before the assumed bit, While */
;/* IEEE places the decimal point after the assumed bit. */
;ieee_exp = msbin[7] - 128 - 1 + 1023;
exp.w = (PeekB(@msbin + 7)&$FF) - 128 - 1 + 1023
;/* First 4 bits of the msbin exponent */
;/* go into the last 4 bits of ieee[7] */
;ieee[7] |= ieee_exp >> 4;
PokeB(@dest + 7, PeekB(@dest + 7) | ((exp >> 4) & $0FFF))
;/* The last 4 bits of msbin exponent */
;/* go into the first 4 bits of ieee[6] */
;ieee[6] |= ieee_exp << 4;
PokeB(@dest + 6, PeekB(@dest + 6) | ((exp << 4) & $FFF0))
;/* The msbin mantissa must be shifted To the right 1 bit. */
;/* Remember that the msbin number has its bytes reversed. */
;For (i=6; i>0; i--)
For i = 6 To 1 Step -1
; {
; msbin[i] <<= 1;
PokeB(@msbin + i, (PeekB(@msbin + i) << 1) & $FE)
; msbin[i] |= msbin[i-1] >> 7;
PokeB(@msbin + i, PeekB(@msbin + i) | ((PeekB(@msbin + i - 1) >> 7) & $01))
; }
Next i
;msbin[0] <<= 1;
PokeB(@msbin, (PeekB(@msbin) << 1) & $FE)
;/* Now the mantissa is put into the ieee array starting in */
;/* the middle of the second To last byte. */
;For (i=6; i>0; i--)
For i=6 To 1 Step -1
; {
; ieee[i] |= msbin[i] >> 4;
PokeB(@dest + i, PeekB(@dest + i) | ((PeekB(@msbin + i) >> 4) & $0F))
; ieee[i-1] |= msbin[i] << 4;
PokeB(@dest + i - 1, PeekB(@dest + i - 1) | ((PeekB(@msbin + i) << 4) & $F0))
; }
Next i
;ieee[0] |= msbin[0] >> 4;
PokeB(@dest, PeekB(@dest) | ((PeekB(@msbin) >> 4) & $0F))
;/* IEEE has a half byte less For its mantissa. If the msbin */
;/* number has anything in this last half byte, then there is */
;/* an overflow. */
; If (msbin[0] & 0x0f)
If (PeekB(@msbin) & $0F)
CallDebugger
Debug "Overflow"
; Return 1;
;Else
;Return 0;
; }
EndIf
ProcedureReturn dest
EndProcedureCode: Select all
Import "MBFIEE32.LIB"
DxToIEEEd(*x.d) As "_DxToIEEEd@4"
DxToIEEEs(*x.s) As "_DxToIEEEs@4"
DxToMBFd(*x.d) As "_DxToMBFd@4"
DxToMBFs(*x.s) As "_DxToMBFs@4"
EndImport
