Configuration Basics
2-8
Am186™CC/CH/CU Microcontrollers User’s Manual
2.7
DATA TYPES
The Am186CC/CH/CU microcontrollers directly support the following data types:
■
Integer: A signed binary numeric value contained in an 8-bit byte or a 16-bit word. All
operations assume a two’s complement representation.
■
Ordinal: An unsigned binary numeric value contained in an 8-bit byte or a 16-bit word.
■
Double Word: A signed binary numeric value contained in two sequential 16-bit
addresses, or in a DX::AX register pair.
■
Quad Word: A signed binary numeric value contained in four sequential 16-bit
addresses.
■
BCD: An unpacked byte representation of the decimal digits 0–9.
■
ASCII: A byte representation of alphanumeric and control characters using the ASCII
standard of character representation.
■
Packed BCD: A packed byte representation of two decimal digits (0–9). Each nibble
(four bits) of the byte contains one digit.
■
Pointer: A 16-bit or 32-bit quantity, composed of a 16-bit offset component or a 16-bit
segment base component in addition to a 16-bit offset component.
■
String: A contiguous sequence of bytes or words. A string can contain from 1 byte up
to 64 Kbytes.
In general, individual data elements must fit within defined segment limits. Figure 2-5
graphically represents the data types supported by the Am186CC/CH/CU microcontrollers.
Table 2-4
Segment Register Selection Rules
Memory Reference
Needed
Segment Register
Used
Implicit Segment Selection Rule
Local Data
Data (DS)
All data references
Instructions
Code (CS)
Instructions (including immediate data)
Stack
Stack (SS)
All stack pushes and pops
Any memory references that use the BP register
External Data (Global)
Extra (ES)
All string instruction references that use the DI
register as an index
Summary of Contents for Am186 CC
Page 1: ...Am186 CC CH CU Microcontrollers User s Manual Order 21914B...
Page 4: ...iv Am186 CC CH CU Microcontrollers User s Manual...
Page 18: ...Table of Contents xviii Am186 CC CH CU Microcontrollers User s Manual...
Page 24: ...Introduction xxiv Am186 CC CH CU Microcontrollers User s Manual...
Page 40: ...Architectural Overview 1 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 86: ...System Overview 3 36 Am186 CC CH CU Microcontrollers User s Manual...
Page 92: ...Emulator Support 4 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 112: ...DRAM Controller 6 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 134: ...Interrupts 7 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 186: ...Programmable I O Signals 9 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 200: ...Watchdog Timer 11 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 232: ...Asynchronous Serial Ports UARTs 13 24 Am186 CC CH CU Microcontrollers User s Manual...
Page 242: ...Synchronous Serial Port SSI 14 10 Am186 CC CH CU Microcontrollers User s Manual...
Page 264: ...High Level Data Link Control HDLC 15 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 332: ...Universal Serial Bus USB 18 34 Am186 CC CH CU Microcontrollers User s Manual...
Page 348: ...Register Summary A 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 376: ...Index Index 18 Am186 CC CH CU Microcontrollers User s Manual...