MC68EC000EI20 Freescale Semiconductor, MC68EC000EI20 Datasheet - Page 15

• Manufacturer Part Number: MC68EC000EI20
• Description: IC MPU 32BIT 20MHZ 68-PLCC
• Manufacturer: Freescale Semiconductor

Specifications of MC68EC000EI20

• Processor Type: M680x0 32-Bit
• Speed: 20MHz
• Voltage: 3.3V, 5V
• Mounting Type: Surface Mount
• Package / Case: 68-PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

Introduction
1.2 FLOATING-POINT UNIT USER PROGRAMMING MODEL
The following paragraphs describe the registers for the floating- point unit user programming
model. Figure 1-2 illustrates the M68000 family user programming model’s floating-point
portion for the MC68040 and the MC68881/MC68882 floating-point coprocessors. It
contains the following registers:
1.2.1 Floating-Point Data Registers (FP7 – FP0)
These floating-point data registers are analogous to the integer data registers for the
M68000 family. They always contain extended- precision numbers. All external operands,
despite the data format, are converted to extended-precision values before being used in
any calculation or being stored in a floating-point data register. A reset or a null-restore
operation sets FP7 – FP0 positive, nonsignaling not-a-numbers (NANs).
1-4
C—Carry
79
• 8 Floating-Point Data Registers (FP7 – FP0)
• 16-Bit Floating-Point Control Register (FPCR)
• 32-Bit Floating-Point Status Register (FPSR)
• 32-Bit Floating-Point Instruction Address Register (FPIAR)
Set if a carry out of the most significant bit of the operand occurs for an addition, or if a
borrow occurs in a subtraction; otherwise clear.
Figure 1-2. M68000 Family Floating-Point Unit User Programming Model
63
M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL
31
31
CONDITION
CODE
0
23
QUOTIENT
15
15
EXCEPTION
EXCEPTION
STATUS
ENABLE
7
7
EXCEPTION
ACCRUED
CONTROL
MODE
0
0
0
FP0
FP1
FP2
FP3
FP4
FP5
FP6
FP7
FPCR
FPSR
FPIAR
FLOATING-POINT
DATA REGISTERS
FLOATING-POINT
CONTROL
REGISTER
FLOATING-POINT
STATUS
REGISTER
FLOATING-POINT
INSTRUCTION
ADDRESS
REGISTER
MOTOROLA