CHAPTER 3. FEATURES OF ARCHITECTURE AND MEMORY MAP
26
P30
P61
P53
(i) SET1
CY
; CY
←
1
AND1
CY, PORT3. 0 ; CY
∧
P30
AND1
CY, PORT6. 1 ; CY
∧
P61
SKT
CY
; CY = 1?
BR
SETP
CLR1
PORT5. 3
;P53
←
0
.
.
SETP: SET1 PORT5. 3
; P53
←
1
(ii) SKT
PORT3. 0
; P30 = 1?
BR
SETP
SKT
PORT6. 1
; P61 = 1?
BR
SETP
CLR1
PORT5. 3
; P53
←
0
.
.
SETP: SET1 PORT5. 3
; P53
←
1
(5)
Specific address bit manipulation addressing (fmem. bit)
An addressing mode to specify each bit of the input/output port, interrupt, etc. flag, etc. of the peripheral hardware
directly by the instruction’s operand. Consequently, the data memory addresses to which this addressing mode is
applied are FB0H to FBFH, FF0H to FFFH.
While the 1-bit direct addressing mode (mem.bit) is applicable only to the bit set/reset/test instructions, this
addressing mode enables multifarious bit manipulation such as the Boolean operation by the AND1, OR1 and XOR1
instructions, test and reset by the SKTCLR instruction in addition to them.
Example
1.
Test the basic interval timer interrupt request flag (IRQBT) and, if set, clear IRQBT and reset the
P63 pin level.
SKTCLR
IRQBT
; IRQBT = 1?
BR
NO
; NO
CLR1
PORT 6. 3
; YES
2.
If P30 and p61 both 1, reset P53.