The AS4040 assembler supports the 4040 microprocessor in-
struction set and can be configured to support only the subset
of instructions used by the 4004 microprocessor.
AS4040 PROCESSOR SPECIFIC DIRECTIVES
.4040 Directive
Format:
.4040
The .4040 directive specifies that the assembler recognize the
complete 4040 instruction set. This is the default instruction
set recognized by the as4040 assembler.
.4004 Directive
Format:
.4004
The .4004 directive specifies that the assembler recognize only
the subset of the 4040 instructions available on the 4004
microprocessor. The unsupported instructions will be flagged
with an 'o' error during assembly.
The .__.CPU. Variable
The assembler variable .__.CPU. is set to indicate the
specific processor selected:
.__.CPU. Processor
-------- ---------
0 4040
1 4004
The variable '.__.CPU.' is by default defined as local and
will not be output to the created .rel file. The assembler com-
mand line options -g or -a will not cause the local symbols to
be output to the created .rel file.
The assembler .globl directive may be used to change the
variable type to global causing its definition to be output to
the rel file. The inclusion of the definition of the variable
'.__.CPU.' might be a useful means of validating that seperately
assembled files have been compiled for the same processor type.
The linker will report an error for variables with multiple non
equal definitions.
4040/4004 REGISTER SET
The following is a list of the 4040/4004 registers used by
AS4040:
r0, r1, r2, r3, - 4-bit registers
r4, r5, r6, r7,
r8, r9, r10, r11,
r12, r13, r14, r15
rp0<r0:r1>, rp1<r2,r3> - 8-bit register pairs
rp2<r4:r5>, rp3<r6:r7>
rp4<r8:r9>, rp5<r10:r11>
rp6<r12:r13>, rp7<r14:r15>
4004/4040 INSTRUCTION SET
Instruction Argument Syntax:
Rn registers R0 - R15
or a value in the range 0 to 15
RPn register pairs RP0 - RP7
or a value in the range 0 to 7
#data immediate 4-bit or 8-bit data
addr call, jump address, or label
cc condition code forms
Mnemonic Binary Jump Condition
-------- ------ --------------
nc 0000 no condition
tz, t0 0001 test equals zero
tn, t1 1001 test equals one
cn, c1 0010 carry equals one
cz, c0 1010 carry equals zero
az, a0 0100 accumulator equals zero
an, nza 1100 accumulator not zero
any single mnemonic
or any ored combination of
tz, cn, az, t0, c1, and a0
or any ored combination of
tn, cz, an, t1, c0, and nza
or any value in the range 0 to 15
are valid condition code arguments.
The mnemonics listed above are predefined
such that a mixed argument like cz|az will
report an 'a' error during assembly.
The terms data and addr may be expressions.
Note that not all addressing modes may be valid with every
instruction. Refer to the 4040/4004 technical data for valid
modes.
The following tables list the mnemonics and arguments recog-
nized by the AS4040 assembler. The extended instructions are
available only in the 4040 microprocessor.
4040/4004 Instructions
Machine Instructions
nop (No Operation)
jcn cc,addr (Jump On Condition, Current Page)
fim RPn,#data (Fetch Immediate To RPn)
src RPn (Send Address From RPn)
fin RPn (Fetch Indirect From ROM Into RPn)
jin RPn (Jump Indirect RPn)
jun addr (Jump Unconditional To ROM Address)
jms addr (Jump To Subroutine ROM Address)
inc Rn (Increment Rn)
isz Rn, addr (Increment Rn, Jump If Rn != 0)
add Rn (Add Rn To A With Carry)
sub Rn (Subtract Rn From A With Borrow)
ld Rn (Load A With Rn)
xch Rn (A <--> Rn)
bbl #data (Branch Back 1 Level, Load A With data)
ldm #data (Load A With data)
Input/Output And RAM Instructions
wrm (A -> Selected RAM Character)
wmp (A -> Selected RAM Output Port)
wrr (A -> Selected ROM Output Port)
wpm (A -> Selected RAM Half Byte)
wr0 (A -> Selected RAM Character 0)
wr1 (A -> Selected RAM Character 1)
wr2 (A -> Selected RAM Character 2)
wr3 (A -> Selected RAM Character 3)
sbm (A <- (A - Slctd RAM Char With Borrow))
rdm (A <- Selected RAM Character)
rdr (A <- Selected ROM Input Port)
adm (A <- (A + Slctd RAM Char With Carry))
rd0 (A <- Selected RAM Character 0)
rd1 (A <- Selected RAM Character 1)
rd2 (A <- Selected RAM Character 2)
rd3 (A <- Selected RAM Character 3)
Accumulator Group Instructions
clb (A <- 0, C <- 0)
clc (C <- 0)
iac (A <- (A + 1))
cmc (Complement Carry)
cma (Complement Accumulator)
ral (Rotate A,C Left)
rar (Rotate A,C Right)
tcc (Tranfer C To Accumulator, Clear C)
dac (A <- (A - 1))
tcs (Transfer Carry Subtract, Clear C)
stc (Set Carry)
daa (Decimal Adjust Accumulator)
kbp (Keyboard Process)
dcl (Designate Command Line)
4040 Specific Instructions
hlt (Halt)
bbs (Branch Back From Interrupt)
lcr (A <- Command Register)
or4 (A <- (R4 or A))
or5 (A <- (R5 or A))
an6 (A <- (R6 and A))
an7 (A <- (R7 and A))
db0 (Designate ROM Bank 0)
db1 (Designate ROM Bank 1)
sb0 (Select Index Register Bank 0, 0 - 7)
sb1 (Select Index Register Bank 1, 0* - 7*)
ein (Enable Interrupt)
din (Disable Interrupt)
rpm (Read Program Memory)
Extended Conditional Jump Instructions
jtz addr - jump if test zero
jtn addr - jump if test not zero
jto addr - jump if test one
jcz addr - jump if carry/link zero
jnc addr - jump if no carry
jco addr - jump if carry/link one
joc addr - jump on carry
jaz addr - jump if accumulator equal to zero
jnz addr - jump if accumulator non zero
jan addr - jump if accumulator non zero
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Last Updated: September 2021