MOVB loc16, AX.MSB
6-198
MOVB loc16, AX.MSB Store MSB of AX Register
SYNTAX OPTIONS OPCODE OBJMODE RPT CYC
MOVB loc16, AX.MSB 1100 100A LLLL LLLL X − 1
Operands loc16 Addressing mode (see Chapter 5)
AX.MS
B
Most significant byte of accumulator high (AH.MSB) or accumulator low
(AL.MSB) register
Description Load 8 bits of the location pointed to by the “loc16” addressing mode with the
most significant byte of the specified AX register (AH.MSB or AL.MSB). The
form of the “loc16” operand determines which of its 8 bits are loaded and
which of its 8 bits are left unchanged:
if(loc16 = *+XARn[offset])
{
if( offset is an even number )
[loc16.LSB] = AX.MSB;
[loc16.MSB] = unchanged;
if( offset is an odd number )
[loc16.LSB] = unchanged;
[loc16.MSB] = AX.MSB;
}
else
[loc16.LSB] = AX.MSB;
[loc16.MSB] = unchanged;
Note: offset = 3-bit immediate or AR0 or AR1 indexed addressing modes only.
This is a read-modify-write operation.
For the following address modes, the returned result is undefined:
*AR6%++ (AMODE = 0)
*0++ (AMODE = x)
*0−− (AMODE = x)
*BR0++ (AMODE = x)
*BR0−− (AMODE = x)
*0++, ARPn (AMODE = 1)
*0−−, ARPn (AMODE = 1)
*BR0++, ARPn (AMODE = 1)
*BR0−−, ARPn (AMODE = 1)
Flags and
Modes
N If (loc16 = @AX), then after the move AX is tested for a negative condition.
The negative flag bit is set if bit 15 of AX is 1, otherwise it is cleared.
Z If (loc16 = @AX), then after the move, AX is tested for a zero condition. The
zero flag bit is set if AX = 0, otherwise it is cleared.