CL-PS7500FE
System-on-a-Chip for Internet Appliance
17. FPA COPROCESSOR MACROCELL ................................................................................156
17.1
FPA Functional Blocks....................................................................................................................157
17.1.1
17.1.2
17.1.3
17.1.4
17.1.5
Coprocessor Interface ....................................................................................................157
Instruction Issuer ............................................................................................................157
The Load-Store Unit .......................................................................................................157
The Register Bank..........................................................................................................157
The Arithmetic Unit.........................................................................................................158
18. FLOATING-POINT COPROCESSOR PROGRAMMER’S MODEL...................................160
18.1
Overview.........................................................................................................................................160
18.1.1
18.1.2
Floating-Point Status Register........................................................................................160
Floating-Point Control Register.......................................................................................160
18.2
18.3
Floating-Point Operation.................................................................................................................160
ARM Integer and Floating-Point Number Formats .........................................................................161
18.3.1
18.3.2
18.3.3
18.3.4
18.3.5
18.3.6
Integer.............................................................................................................................161
IEEE Single Precision (S)...............................................................................................161
IEEE Double Precision (D) .............................................................................................161
IEEE Extended Double Precision (E) .............................................................................162
Packed Decimal (P) ........................................................................................................163
Expanded Packed Decimal (EP).....................................................................................163
18.4
18.5
The Floating-Point Status Register (FPSR)....................................................................................164
18.4.1
18.4.2
18.4.3
18.4.4
System ID Byte...............................................................................................................164
Exception Trap Enable Byte............................................................................................165
System Control Byte.......................................................................................................165
Cumulative Exception Flags Byte...................................................................................166
The Floating-Point Control Register (FPCR) ..................................................................................168
19. FLOATING-POINT INSTRUCTION SET.............................................................................170
19.1
Coprocessor Data Transfer.............................................................................................................170
19.1.1
19.1.2
19.1.3
19.1.4
19.1.5
LDF/STF — Load and Store Floating .............................................................................170
Assembler Syntax...........................................................................................................171
Load and Store Multiple Floating Instructions ................................................................172
Assembler Syntax — Form 1..........................................................................................173
Assembler Syntax — Form 2..........................................................................................174
19.2
Coprocessor Data Operations........................................................................................................174
19.2.1
19.2.2
19.2.3
19.2.4
Dyadic Operations ..........................................................................................................174
Monadic Operations........................................................................................................175
Library Calls....................................................................................................................175
Backwards Compatibility.................................................................................................175
19.3
19.4
Coprocessor Register Transfer .......................................................................................................178
19.3.1 Compare Operations ......................................................................................................179
FPA Instruction Set........................................................................................................................180
19.4.1
19.4.2
Infinities and NaNs..........................................................................................................180
Exceptional Conditions ...................................................................................................180
19.5
19.6
Floating-point Support Code ..........................................................................................................182
19.5.1 IEEE Standard Conformance .........................................................................................182
Instruction Cycle Timing .................................................................................................................183
19.6.1
19.6.2
Instruction Classification.................................................................................................184
Performance Tuning........................................................................................................185
June 1997
9
ADVANCE DATA BOOK v2.0
TABLE OF CONTENTS
CIRRUS [ CIRRUS LOGIC ]
