2650 REGISTER SET
The following is a list of the 2650 registers used by AS2650:
r0,r1 - 8-bit accumulators
r2,r3
2650 INSTRUCTION SET
The following tables list all 2650 mnemonics recognized by
the AS2650 assembler. The designation [] refers to a required
addressing mode argument. The designation CC refers to a re-
quired condition code argument: .eq., .gt., .lt., .un., or
value of 0-3. The following list specifies the format for each
addressing mode supported by AS2650:
#data immediate byte data
r0,r1,r2,r3 registers
addr location/branch address
[addr] or indirect addressing
@addr
[addr,r0] or register indexed
@addr,r0 indirect addressing
[addr,-r0] or autodecrement register indexed
@addr,-r0 indirect addressing
[addr,r0+] or autoincrement register indexed
@addr,r0+ indirect addressing
AS2650 ASSEMBLER PAGE AB-2
2650 INSTRUCTION SET
.eq. CC: equal (== 0)
.gt. CC: greater than (== 1)
.lt. CC: less than (== 2)
.un. CC: unconditional (== 3)
The terms data, label, and addr may all be expressions.
Note that not all addressing modes are valid with every in-
struction, refer to the 2650 technical data for valid modes.
Load / Store Instructions
lodz r lodi #data
lodr [] loda []
stoz r
stor [] stoa []
Arithmetic / Compare Instructions
addz r addi #data
addr [] adda []
subz r subi #data
subr [] suba []
comz r comi #data
comr [] coma []
dar r
Logical / Rotate Instructions
andz r andi #data
andr [] anda []
iorz r iori #data
iorr [] iora []
eorz r eori #data
eorr [] eora []
rrr r
rrl r
Condition Code Branches
bctr CC,[] bcta CC,[]
bcfr CC,[] bcfa CC,[]
bstr CC,[] bsta CC,[]
bsfr CC,[] bsta CC,[]
Register Test Branches
brnr r,[] brna r,[]
birr r,[] bira r,[]
bdrr r,[] bdra r,[]
bsnr r,[] bsna r,[]
Branches (to Subroutines) / Returns
bxa [] bsxa []
zbrr [] zbsr []
retc CC rete CC
Input / Output
redc r wrtc r
redd r wrtd r
rede r,addr wrte r,addr
Miscellaneos
halt nop
tmi r,#data
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Last Updated: September 2023