Freescale Semiconductor MC68881 - Page 93

FCOS Cosine FCOS
Instruction Format:
15 14 13
1 1 1
0 RIM 0
12 11 10 9 8 7 6 5 4 3 2 1 0
COPROCESSOR 1 EFFECTIVE
ADDRESS
1 ID I O 0 O MODE REGISTER
SOURCE DESTINATION
II"[
SPECIFIER REGISTER 0011101
Instruction Fields:
Coprocessor ID Field -~- Specifies which coprocessor in the system is to execute this
instruction. Freescale assemblers default to ID = 1 for the FPCP.
Effective Address Field -- Determines the addressing mode for external operands.
If R/M=O, this field is unused, and should contain zeros.
If R/M = 1, this field is encoded with an M68000 addressing mode as shown:
Addressing Mode Mode Register
Dn* 000 reg. number:Dn
An -- --
(An) 010
reg. number:An
(An)+ 011 reg. number:An
- (An) 100 reg. number:An
[d16,An) 101 reg. number:An
(d8,An,Xn) 110 reg. number:An
(bd,An,Xn) 110 reg. number:An
(lbd,An,XnJ,od) 110 reg. number:An
([bd,An],Xn,od) 110 reg. number:An
Addressing Mode Mode
{xxx}.W 111
(xxx).L 111
#<data > 111
(d 16,PC) 111
(do,PC,Xn) 111
(bd,PC,Xn) 111
(Ibd,PC, Xn],od) 111
([bd,PC],Xn,od) 111
Register
OOO
001
100
010
011
011
011
011
*Only if <fret> is Byte, Word, Long, or Single,
R/M Field -- Specifies the source operand address mode.
0 -- The operation is register to register.
1 -- The operation is <ea> to register.
Source Specifier Field -- Specifies the source register or data format.
If R/M = 0, specifies the source floating-point data register, FPm.
If R/M = 1, specifies the source data format:
000 L Long Word Integer
001 S Single Precision Real
010 X Extended Precision Real
011 P Packed Decimal Real
100 W Word Integer
101 D Double Precision Real
110 B Byte Integer
Destination Register Field-- Specifies the destination floating-point data register, FPn.
If R/M =0 and the source and destination,fields are equal, then the input operand
is taken from the specified floating-point data register, and the result is written into
the same register. If the single register syntax is used, Freescale assemblers set the
source and destination fields to the same value.
MC68881/MC68882 USER'S MANUAL FREESCALE
4-35