Motorola 68000

11
The 68000's Instruction Set
those that branch on an unsigned condition and those that branch
on a signed condition. For example, $FF is greater than $10 when
the numbers are regarded as unsigned (i.e., 255 is greater than
16). However, if the numbers are signed, $FF is less than $10 (i.e.,
-1 is less than 16).
The signed comparisons are:
BGE branch on greater than or equal
BGT branch on greater than
BLE branch on lower than or equal
BLT branch on less than
The unsigned comparisons are:
BHS BCC branch on higher than or same
BHI branch on higher than
BLS branch on lower than or same
BLO BCS branch on less than
The official mnemonics BCC (branch on carry clear) and BCS (branch
on carry set) can be renamed as BHS (branch on higher than or
same) and BLO (branch on less than), respectively. Many 68000
assemblers support these alternative mnemonics.
Condition codes: X N Z V C
- - - - -
BCHG Test a bit and change
Operation: [Z] ← <bit number> OF [destination]
<bit number> OF [destination] ← <bit number> OF [destination]
Syntax: BCHG Dn,<ea>
BCHG #<data>,<ea>
Attributes: Size = byte, longword
Description: A bit in the destination operand is tested and the state of the
specified bit is reflected in the condition of the Z-bit in the CCR.
After the test operation, the state of the specified bit is changed
in the destination. If a data register is the destination, then the bit
numbering is modulo 32, allowing bit manipulation of all bits in
a data register. If a memory location is the destination, a byte is