ACKNOWLEDGMENT
Thanks to Marko Makela for his contribution of the AS6500
cross assembler.
Marko Makela
Sillitie 10 A
01480 Vantaa
Finland
Internet: Marko.Makela@Helsinki.Fi
EARN/BitNet: msmakela@finuh
Several additions and modifications were made to his code to
support the following families of 6500 processors:
(1) 650X and 651X processor family
(2) 65F11 and 65F12 processor family
(3) 65C00/21 and 65C29 processor family
(4) 65C02, 65C102, and 65C112 processor family
The instruction syntax of this cross assembler contains two
peculiarities: (1) the addressing indirection is denoted by the
square brackets [] and (2) the `bbrx' and `bbsx' instructions
are written `bbr0 memory,label'.
.enabl and .dsabl Directives
Format:
.enabl (arg1, arg2, ...)
.dsabl (arg1, arg2, ...)
where: arg1, arg2, ... represent one or more
of the following options
autodpcnst Automatic Direct Paging For Constants
autodpsmbl Automatic Direct Paging For Symbols
autodpcnst: controls whether constants within the range of
0x0000-0x00FF (paging region) or external are automatically as-
sembled as paged variables. The paging area must have been
specified for this option to take effect. The default is
enabled.
autodpsmbl: controls whether symbols within the range of
0x0000-0x00FF (paging region) or external are automatically as-
sembled as paged variables. The paging area must have been
specified for this option to take effect. The default is
enabled.
.dpgbl Directive
Format:
.dpgbl arg1, arg2, ...
Where the arguments are labels or
symbols with values that are in the
0x0000-0x00FF direct page. If the
page area has not been specified
then the arguments are defined as
being in the current area.
6500 REGISTER SET
The following is a list of the 6500 registers used by AS6500:
a - 8-bit accumulator
x,y - index registers
6500 INSTRUCTION SET
The following tables list all 6500 family mnemonics recog-
nized by the AS6500 assembler. The designation [] refers to a
required addressing mode argument. The following list specifies
the format for each addressing mode supported by AS6500:
#data immediate data
byte or word data
*dir direct page addressing
(see .setdp directive)
0 <= dir <= 255
offset,x indexed addressing
offset,y indexed addressing
address = (offset + (x or y))
[offset,x] pre-indexed indirect addressing
0 <= offset <= 255
address = contents of location
(offset + (x or y)) mod 256
[offset],y post-indexed indirect addressing
address = contents of location at offset
plus the value of the y register
[address] indirect addressing
ext extended addressing
label branch label
address,label direct page memory location
branch label
bbrx and bbsx instruction addressing
The terms data, dir, offset, address, ext, and label may all be
expressions.
Note that not all addressing modes are valid with every in-
struction, refer to the 65xx technical data for valid modes.
Processor Specific Directives
The AS6500 cross assembler has four (4) processor specific
assembler directives which define the target 65xx processor
family:
.r6500 Core 650X and 651X family (default)
.r65f11 Core plus 65F11 and 65F12
.r65c00 Core plus 65C00/21 and 65C29
.r65c02 Core plus 65C02, 65C102, and 65C112
65xx Core Inherent Instructions
brk clc
cld cli
clv dex
dey inx
iny nop
pha php
pla plp
rti rts
sec sed
sei tax
tay tsx
txa txs
tya
65xx Core Branch Instructions
bcc label bhs label
bcs label blo label
beq label bmi label
bne label bpl label
bvc label bvs label
65xx Core Single Operand Instructions
asl []
dec []
inc []
lsr []
rol []
ror []
65xx Core Double Operand Instructions
adc []
and []
bit []
cmp []
eor []
lda []
ora []
sbc []
sta []
65xx Core Jump and Jump to Subroutine Instructions
jmp [] jsr []
65xx Core Miscellaneous X and Y Register Instructions
cpx []
cpy []
ldx []
stx []
ldy []
sty []
65F11 and 65F12 Specific Instructions
bbr0 [],label bbr1 [],label
bbr2 [],label bbr3 [],label
bbr4 [],label bbr5 [],label
bbr6 [],label bbr7 [],label
bbs0 [],label bbs1 [],label
bbs2 [],label bbs3 [],label
bbs4 [],label bbs5 [],label
bbs6 [],label bbs7 [],label
rmb0 [] rmb1 []
rmb2 [] rmb3 []
rmb4 [] rmb5 []
rmb6 [] rmb7 []
smb0 [] smb1 []
smb2 [] smb3 []
smb4 [] smb5 []
smb6 [] smb7 []
65C00/21 and 65C29 Specific Instructions
bbr0 [],label bbr1 [],label
bbr2 [],label bbr3 [],label
bbr4 [],label bbr5 [],label
bbr6 [],label bbr7 [],label
bbs0 [],label bbs1 [],label
bbs2 [],label bbs3 [],label
bbs4 [],label bbs5 [],label
bbs6 [],label bbs7 [],label
bra label
phx phy
plx ply
rmb0 [] rmb1 []
rmb2 [] rmb3 []
rmb4 [] rmb5 []
rmb6 [] rmb7 []
smb0 [] smb1 []
smb2 [] smb3 []
smb4 [] smb5 []
smb6 [] smb7 []
65C02, 65C102, and 65C112 Specific Instructions
bbr0 [],label bbr1 [],label
bbr2 [],label bbr3 [],label
bbr4 [],label bbr5 [],label
bbr6 [],label bbr7 [],label
bbs0 [],label bbs1 [],label
bbs2 [],label bbs3 [],label
bbs4 [],label bbs5 [],label
bbs6 [],label bbs7 [],label
bra label
phx phy
plx ply
rmb0 [] rmb1 []
rmb2 [] rmb3 []
rmb4 [] rmb5 []
rmb6 [] rmb7 []
smb0 [] smb1 []
smb2 [] smb3 []
smb4 [] smb5 []
smb6 [] smb7 []
stz []
trb []
tsb []
Additional addressing modes for the following core instruc-
tions are also available with the 65C02, 65C102, and 65C112 pro-
cessors.
adc [] and []
cmp [] eor []
lda [] ora []
sbc [] sta []
bit [] jmp []
dec inc
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Last Updated: September 2023