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6.33.14 Parameter Block for SVC_REQ 57
Address+0 Memory type. Refer to Memory Type Codes above.
Address+1 The zero-based offset N to write to nonvolatile storage. Contains the complete offset for any
memory area except %W, which also requires the use of address + 2 for offsets greater
Address+2
than 65,535.
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For %I, %Q, %M, %T, and %G memory in byte mode, N = (Ra - 1) / 8, where Ra = one-based
reference address. For example, to read from the one-based bit reference address %T33,
enter the byte offset 4: (33 - 1) / 8 = 4.
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For %W, %R, %AI, and %AQ memory, and for %I, %Q, %M, %T, and %G memory in bit mode,
N = Ra - 1. For example, to read from the one-based reference address %R200, enter the
zero-based reference offset 199; to read from %I73 in bit mode, enter offset 72. For
memory-in-bit mode, the offset must be set on a byte boundary, that is, a number exactly
divisible by 8: 0, 8, 16, 24, and so on.
Address+3 Length. The number of items to write to nonvolatile storage beginning at the reference address
calculated from the offset defined at [address + 1 and address + 2]. The length can be one of the
following:
Description
The number of words (16-bit registers) to read
from %W, %R, %AI, or %AQ nonvolatile storage
The number of bytes to read from %I, %Q, %M, %T,
or %G in byte mode nonvolatile storage
The number of bits to read from %I, %Q, %M, %T,
or %G in bit mode nonvolatile storage
The value must reside in the low byte of address + 3. The high byte must be set to zero.
Address + 4 When bit 0 is set to 1,
logic in RAM has changed since nonvolatile storage was read or written.
Bits 1 through 15 must be set to zero; otherwise, the write fails.
Address+5 Reserved. Value must be set to zero.
Address+6 Response status. The low byte contains the major error code; the high byte contains the minor
error code.
Address+7 Count of items written: Words, bytes or bits. Calculated from the first word that changed to the
end of the array.
Address+8
The number of bytes available in nonvolatile storage.
Address+9
Address+10
Reserved.
Address+11
GFK-2950C
Storage Disabled Conditions
February 2018
Chapter 6. Service Request Function
Valid range
1 through 32 words
1 through 64 bytes
1 through 512 bits in
increments of 8 bits
are ignored. A write is allowed even if the
339
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