[<<Previous Entry]
[^^Up^^]
[Next Entry>>]
[Menu]
[About The Guide]
INT 3E - FLOATING POINT EMULATION - Borland LANGUAGES "SHORTCUT" CALL
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
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
See Also:
3D
This page created by ng2html v1.05, the Norton guide to HTML conversion utility.
Written by Dave Pearson