NEC PD750008 - Manual (Page 316)

296
µPD750008 USER'S MANUAL
GETI taddr
Function: taddr = T
5-0
, 0 : 20H-7FH
For the µPD750008
[Mk I mode]
• When a table defined by the TBR instruction is referenced
PC
12-0
<– (taddr)
4-0
+ (taddr+1)
• When a table defined by the TCALL instruction is referenced
(SP–1) <– PC
7-4
, (SP–2) <– PC
3-0
(SP–3) <– MBE, RBE, 0, PC
12
(SP–4) <– PC
11-8
PC
12-0
<– (taddr)
4-0
+ (taddr+1)
SP <– SP–4
• When a table defined by an instruction other than the TBR or TCALL instruction is
referenced
An instruction using (taddr) (taddr+1) as its operation code is executed.
[Mk II mode]
• When a table defined by the TBR instruction is referenced
PC
12-0
<– (taddr)
4-0
+ (taddr+1)
• When a table defined by the TCALL instruction is referenced
(SP–2) <– x, x, MBE, RBE
(SP–3) <– PC
7-4
, (SP–4) <– PC
3-0
(SP–5) <– 0, 0, 0, PC
12
, (SP–6) <– PC
11-8
PC
12-0
<– (taddr)
4-0
+ (taddr+1)
SP <– SP–6
• When a table defined by an instruction other than the TBR or TCALL instruction is
referenced
An instruction using (taddr) (taddr+1) as its operation code is executed.
Remark "Function" in this section is applicable to the µPD750008 whose program counter consists of
13 bits (addr = 0000H to 1FFFH).
However, this is also applicable to the µPD750004 whose program counter consists of 12
bits (addr = 0000H to 0FFFH), the µPD750006 whose program counter consists of 13 bits
(addr = 0000H to 17FFH), and the µPD75P0016 whose program counter consists of 14 bits
(addr = 0000H to 3FFFH).
The 2-byte data at the program memory addresses specified by (taddr) and (taddr+1) is referenced and
executed as an instruction.
Addresses 0020H to 007FH are used as a reference table area. Data must be written to this area
beforehand. When a 1-byte instruction or 2-byte instruction is written, its mnemonic can be used directly.
For a 3-byte call instruction or 3-byte branch instruction, an assembler pseudo instruction (TCALL, TBR)
is used.
Only an even address can be specified as taddr.
I/II