Intel 8253 - Page 73

Intel387
TM
SX MATH COPROCESSOR
Encoding Clock Count Range
Instruction
Byte 0 Byte 1
Optional 32-Bit 32-Bit 64-Bit 16-Bit
Bytes 2–6 Real Integer Real Integer
CONSTANTS
FLDZ
e
Load
a
0.0 to ST(0) ESC 001 1110 1110 10–17
FLD1
e
Load
a
1.0 to ST(0) ESC 001 1110 1000 15–22
FLDPI
e
Load q to ST(0) ESC 001 1110 1011 26–36
FLDL2T
e
Load log
2
(10) to ST(0) ESC 001 1110 1001 26– 36
FLDL2E
e
Load log
2
(e) to ST(0) ESC 001 1110 1010 26–36
FLDLG2
e
Load log
10
(2) to ST(0) ESC 001 1110 1100 25 – 35
FLDLN2
e
Load log
e
(2) to ST(0) ESC 001 1110 1101 26– 38
PROCESSOR CONTROL
FINIT
e
Initialize Math CoProcessor ESC 011 1110 0011 33
FLDCW
e
Load control word from memory ESC 001 MOD 101 R/M SIB/DISP 19
FSTCW
e
Store control word to memory ESC 001 MOD 111 R/M SIB/DISP 15
FSTSW
e
Store status word to memory ESC 101 MOD 111 R/M SIB/DISP 15
FSTSW AX
e
Store status word to AX ESC 111 1110 0000 13
FCLEX
e
Clear exceptions ESC 011 1110 0010 11
FSTENV
e
Store environment ESC 001 MOD 110 R/M SIB/DISP 117–118
FLDENV
e
Load environment ESC 001 MOD 100 R/M SIB/DISP 85
FSAVE
e
Save state ESC 101 MOD 110 R/M SIB/DISP 402–403
FRSTOR
e
Restore state ESC 101 MOD 100 R/M SIB/DISP 415
FINCSTP
e
Increment stack pointer ESC 001 1111 0111 21
FDECSTP
e
Decrement stack pointer ESC 001 1111 0110 22
FFREE
e
Free ST(i) ESC 101 1100 0 ST(i) 18
FNOP
e
No operations ESC 001 1101 0000 12
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