ColdFire Core
7-10
Freescale Semiconductor
MCF51CN128 Reference Manual, Rev. 6
7.3.2
Exception Processing Overview
Exception processing for ColdFire processors is streamlined for performance. The ColdFire processors
differ from the M68000 family because they include:
•
A simplified exception vector table
•
Reduced relocation capabilities using the vector-base register
•
A single exception stack frame format
•
Use of separate system stack pointers for user and supervisor modes.
Table 7-5. Instruction Enhancements over Revision ISA_A
Instruction
Description
BITREV
The contents of the destination data register are bit-reversed; that is, new Dn[31] equals old
Dn[0], new Dn[30] equals old Dn[1], ..., new Dn[0] equals old Dn[31].
BYTEREV
The contents of the destination data register are byte-reversed; that is, new Dn[31:24] equals
old Dn[7:0], ..., new Dn[7:0] equals old Dn[31:24].
FF1
The data register, Dn, is scanned, beginning from the most-significant bit (Dn[31]) and ending
with the least-significant bit (Dn[0]), searching for the first set bit. The data register is then
loaded with the offset count from bit 31 where the first set bit appears.
MOV3Q.L
Moves 3-bit immediate data to the destination location.
Move from USP
User Stack Pointer
→
Destination register
Move to USP
Source register
→
User Stack Pointer
MVS.{B,W}
Sign-extends source operand and moves it to destination register.
MVZ.{B,W}
Zero-fills source operand and moves it to destination register.
SATS.L
Performs saturation operation for signed arithmetic and updates destination register,
depending on CCR[V] and bit 31 of the register.
TAS.B
Performs indivisible read-modify-write cycle to test and set addressed memory byte.
Bcc.L
Branch conditionally, longword
BSR.L
Branch to sub-routine, longword
CMP.{B,W}
Compare, byte and word
CMPA.W
Compare address, word
CMPI.{B,W}
Compare immediate, byte and word
MOVEI
Move immediate, byte and word to memory using Ax with displacement
STLDSR
Pushes the contents of the status register onto the stack and then reloads the status register
with the immediate data value.
