Operation:
If (condition true) then PC + d -->; PC
Compatibility: 68000 Family
Assembler Syntax:
Bcc <label>
Attributes: Size = (Byte, Word, Long*)
*(MC68020, MC68030, MC68040 only)
Description: If the specified condition is true, program exe-
cution continues at location (PC) + displacement. The PC
contains the address of the instruction word of the Bcc
instruction plus two. The displacement is a twos compliment
integer that represents the relative distance in bytes from the
current PC to the 16-bit displacement (the word immediately
following the instruction) is used. If the 8-bit displacement
field in the instruction word is all ones ($FF), the 32-bit
displacement (long word immediately following the inst-
ruction) is used. Condition code cc specifies one of the
following conditions.
CC carry clear 0100 /C
CS carry set 0101 C
EQ equal 0111 Z
GE greater or equal 1100 N � V + /N � /V
GT greater than 1110 N � V � /Z + /N � /V � /Z
HI high 0010 /C � /Z
LE less or equal 1111 Z + N � /V + /N � V
LS low or same 0011 C + Z
LT less than 1101 N � /V + /N � V
MI minus 1011 N
NE not equal 0110 /Z
PL plus 1010 /N
VC overflow clear 1000 /V
VS overflow set 1001 V
Condition Codes:
Not affected.
Instruction Format:
\i3-++-4Condition,88-bit Displacement,016-bit Displacement if 8-bit Displacement = $00,032-bit Displacement if 8-bit Displacement = $FF,
Instruction Fields (Register Shifts):
Condition field -- The binary code for one of the
conditions listed in the table.
8-bit Displacement field -- Twos complement integer
specifying the number of bytes between the branch
instruction and the next instruction to be executed
if the condition is met.
16-bit Displacement field -- Used for the displacement when
the 8-bit displacement field contains $00.
32-bit Displacement field -- Used for the displacement when
the 8-bit displacement field contains $FF.
Note: A branch to the immediately following instruction auto-
matically uses the 16-bit displacement format because
the 8-bit displacement field contains $00 (zero offset).