GMS81C1102 / GMS81C1202
reduce program byte length by using 2 bytes PCALL in-
stead of 3 bytes CALL instruction. If it is frequently called,
it is more useful to save program byte length.
Example: Usage of TCALL
LDA
#5
TCALL 0FH
;
;
;
1BYTE INSTRUCTION
INSTEAD OF 3 BYTES
NORM AL CALL
:
:
Table Call (TCALL) causes the CPU to jump to each
TCALL address, where it commences the execution of the
service routine. The Table Call service area spaces 2-byte
for every TCALL: 0FFC0H for TCALL15, 0FFC2H for
TCALL14, etc., as shown in Figure 12-5 .
;
;TABLE CALL ROUTINE
;
FUNC_A: LDA
LRG0
RET
;
FUNC_B: LDA
LRG1
2
1
RET
;
;TABLE CALL ADD. AREA
;
ORG
DW
0FFC0H
FUNC_A
FUNC_B
;
TCALL ADDRESS AREA
DW
Address
Program Memory
TCALL 15
TCALL 14
TCALL 13
TCALL 12
TCALL 11
TCALL 10
TCALL 9
0FFC0H
C1
C2
C3
C4
C5
C6
C7
C8
C9
CA
CB
CC
CD
CE
CF
Address
0FF00H
PCALL Area Memory
PCALL Area
(256 Bytes)
TCALL 8
0FFFFH
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
DA
DB
DC
DD
DE
DF
TCALL 7
TCALL 6
TCALL 5
TCALL 4
TCALL 3
TCALL 2
TCALL 1
TCALL 0 / BRK *
NOTE:
* means that the BRK software interrupt is using
same address with TCALL0.
Figure 12-5 PCALL and TCALL Memory Area
Jan. 2002 ver 2.0
29
HYNIX [ HYNIX SEMICONDUCTOR ]
