ACKNOWLEDGMENT
Thanks to Uwe Steller for his contribution of the AS740
cross assembler.
Uwe Stellar
Uwe dot Steller at t-online dot de
The instruction syntax of this cross assembler uses the
square brackets [] to denote addressing indirection.
740 REGISTER SET
The following is a list of the 740 registers used by AS740:
a - 8-bit accumulator
x,y - index registers
740 INSTRUCTION ADDRESSING MODES
The following list specifies the format for each
addressing mode supported by AS740:
#data immediate data byte
#data,*zp immediate data to zero page
a accumulator addressing
*zp zero page addressing
(see .setdp directive)
0 <= dir <= 255
*zp,x zero page x addressing
*zp,y zero page y addressing
address = (offset + (x or y))
[*zp,x] indirect x addressing
0 <= offset <= 255
address = 2 bytes at location
[(offset + (x or y)) mod 256]
[*zp],y indirect y addressing
address = 2 byte value at offset
plus the value of the y register
abs absolute addressing (2 byte)
abs,x absolute x addressing (2 byte + x)
abs,y absolute y addressing (2 byte + y)
[abs] indirect addressing (2 byte)
label branch label
\special low order byte of address 0xFFnn
BIT#,*zp bit set/clear zero page
BIT#,A bit set/clear accumulator
BIT#,*zp,label branch on bit set/clear in zero page
BIT#,A,label branch on bit set/clear in accumulator
The terms data, zp, abs, BIT , special, and label may all be ex-
pressions.
Note that not all addressing modes are valid with every in-
struction, refer to the 740 technical data for valid modes.
740 INSTRUCTION SET
The following tables list all 740 family mnemonics recog-
nized by the AS740 assembler. The designation [] refers to a
required addressing mode argument.
Inherent Instructions
brk clc
cld cli
clt clv
dex dey
inx iny
nop pha
php pla
plp rti
rts sec
sed sei
set stp
tax tay
tsx txa
txs tya
wit
Branch Instructions
bcc label bhs label
bcs label blo label
beq label bmi label
bne label bpl label
bvc label bvs label
bra label
Single Operand Instructions
asl []
dec []
inc []
lsr []
rol []
ror []
Double Operand Instructions
adc []
and []
bit []
cmp []
eor []
lda []
ora []
sbc []
sta []
Jump and Jump to Subroutine Instructions
jmp [] jsr []
Miscellaneous X and Y Register Instructions
cpx []
cpy []
ldx []
stx []
ldy []
sty []
Bit Instructions
bit []
bbc BIT#,[],label bbs BIT#,[],label
clb BIT#,[] seb BIT#,[]
Other Instructions
div [] mul []
ldm #imm,[] com []
tst [] rrf []
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