Int 3E  - Floating Point Emulation - Borland LANguages "shortcut" Call     [r]


Notes: the two bytes following the INT 3E instruction are the subcode and
     a NOP (90h), except for subcodes DCh and DEh, where the second byte
     is a register count (01h-08h)
   this vector is modified but not restored by Direct Access v4.0, and
     may be left dangling by other programs written with the same version
     of compiled BASIC

See Also: INT 3D

Values for subcode:
Subcode        Function
 DCh   load 8086 stack with 8087 registers; overwrites the 10*N bytes at the
     top of the stack prior to the INT 3E with the 8087 register contents
 DEh   load 8087 registers from top of 8086 stack; ST0 is furthest from top
     of 8086 stack
 E0h   round TOS and R1 to single precision, compare, pop twice
     returns AX=8087 status word, FLAGS=8087 condition bits
 E2h   round TOS and R1 to double precision, compare, pop twice
     returns AX=8087 status word, FLAGS=8087 condition bits

   Note: buggy in TPas5.5, because it sets the 8087 precision control
     field to the undocumented value 01h; this results in actually
     rounding to single precision
 E4h   compare TOS/R1 with two POP's
     returns FLAGS=8087 condition bits
 E6h   compare TOS/R1 with POP
     returns FLAGS=8087 condition bits
 E8h   FTST (check TOS value)
     returns FLAGS=8087 condition bits
 EAh   FXAM (check TOS value)
     returns AX=8087 status word
 ECh   sine(ST0)
 EEh   cosine(ST0)
 F0h   tangent(ST0)
 F2h   arctangent(ST0)
 F4h   ST0 = ln(ST0)
 F6h   ST0 = log2(ST0)
 F8h   ST0 = log10(ST0)
 FAh   ST0 = e**ST0
 FCh   ST0 = 2**ST0
 FEh   ST0 = 10**ST0