396
ECALL, ECALLP
(4) When function devices (FX, FY, FD) are used by a subroutine program, specify a device corresponding to the function
device with to . The contents of the devices specified by to are as indicated below.
(a) Prior to execution of the subroutine program, bit data is transmitted to FX, and word data is transmitted to FD.
(b) After the execution of the subroutine program, the contents of FY and FD are transmitted to the corresponding
devices.
(c) The processing units for the function devices are as follows:
• FX, FY: Bits
• FD : 4-word units
The size of the data to be dealt with will differ depending on the device specified in the argument. The device
specified as a function device should be secured for the data size. An error will occur if it cannot be secured for the
data size.
*1:
An error will not occur even when the device number specified by
to
is not a multiple of 16 at the digit designation of the
bit device.
[Main routine program]
(5) From to can be used by the ECALL instruction.
(6) The device used in the argument of the ECALL instruction should not be used in a subroutine program.
If used, it will not be possible to obtain accurate calculations. (Refer to the following program example.)
Function devices
Device
Data Size
Remark
• FX
• FY
Bit device
1 point
––––
When Bit Designation has been Made for Word Device
1 bit
• FD
When digit designation of a bit device is used*1
4 words
The data size varies depending
on the instruction to be used.
Word device
4 words
S1
S5
S1
S5
[MAIN]
[ABC]
S1
S5
Occupies from D0 to D3
(
Transfer to FD1
)
.
X0
D30
Occupies from D30 to D33
(
Transfer to FD2
)
.
Occupies M0
(
Transfer to FX0
)
.
D0
M0
P0
ECALL "A-LINE"
S1
S5