#include "ehead.h" void emovi(), emovo(), ecleaz(), eshdn8(), emdnorm(); void todec(); /* ; convert DEC double precision to e type ; double d; ; short e[NE]; ; dectoe( &d, e ); */ void dectoe( d, e ) unsigned short *d; unsigned short *e; { unsigned short y[NI]; register unsigned short r, *p; ecleaz(y); /* start with a zero */ p = y; /* point to our number */ r = *d; /* get DEC exponent word */ if( *d & (unsigned int )0x8000 ) *p = 0xffff; /* fill in our sign */ ++p; /* bump pointer to our exponent word */ r &= 0x7fff; /* strip the sign bit */ if( r == 0 ) /* answer = 0 if high order DEC word = 0 */ goto done; r >>= 7; /* shift exponent word down 7 bits */ r += EXONE - 0201; /* subtract DEC exponent offset */ /* add our e type exponent offset */ *p++ = r; /* to form our exponent */ r = *d++; /* now do the high order mantissa */ r &= 0177; /* strip off the DEC exponent and sign bits */ r |= 0200; /* the DEC understood high order mantissa bit */ *p++ = r; /* put result in our high guard word */ *p++ = *d++; /* fill in the rest of our mantissa */ *p++ = *d++; *p = *d; eshdn8(y); /* shift our mantissa down 8 bits */ done: emovo( y, e ); } /* ; convert e type to DEC double precision ; double d; ; short e[NE]; ; etodec( e, &d ); */ #if 0 static unsigned short decbit[NI] = {0,0,0,0,0,0,0200,0}; void etodec( x, d ) unsigned short *x, *d; { unsigned short xi[NI]; register unsigned short r; int i, j; emovi( x, xi ); *d = 0; if( xi[0] != 0 ) *d = 0100000; r = xi[E]; if( r < (EXONE - 128) ) goto zout; i = xi[M+4]; if( (i & 0200) != 0 ) { if( (i & 0377) == 0200 ) { if( (i & 0400) != 0 ) { /* check all less significant bits */ for( j=M+5; j<NI; j++ ) { if( xi[j] != 0 ) goto yesrnd; } } goto nornd; } yesrnd: eaddm( decbit, xi ); r -= enormlz(xi); } nornd: r -= EXONE; r += 0201; if( r < 0 ) { zout: *d++ = 0; *d++ = 0; *d++ = 0; *d++ = 0; return; } if( r >= 0377 ) { *d++ = 077777; *d++ = -1; *d++ = -1; *d++ = -1; return; } r &= 0377; r <<= 7; eshup8( xi ); xi[M] &= 0177; r |= xi[M]; *d++ |= r; *d++ = xi[M+1]; *d++ = xi[M+2]; *d++ = xi[M+3]; } #else extern int rndprc; void etodec( x, d ) unsigned short *x, *d; { unsigned short xi[NI]; long exp; int rndsav; emovi( x, xi ); exp = (long )xi[E] - (EXONE - 0201); /* adjust exponent for offsets */ /* round off to nearest or even */ rndsav = rndprc; rndprc = 56; emdnorm( xi, 0, 0, exp, 64 ); rndprc = rndsav; todec( xi, d ); } void todec( x, y ) unsigned short *x, *y; { unsigned short i; unsigned short *p; p = x; *y = 0; if( *p++ ) *y = 0100000; i = *p++; if( i == 0 ) { *y++ = 0; *y++ = 0; *y++ = 0; *y++ = 0; return; } if( i > 0377 ) { *y++ |= 077777; *y++ = 0xffff; *y++ = 0xffff; *y++ = 0xffff; return; } i &= 0377; i <<= 7; eshup8( x ); x[M] &= 0177; i |= x[M]; *y++ |= i; *y++ = x[M+1]; *y++ = x[M+2]; *y++ = x[M+3]; } #endif