ST7 REGISTER SET
The following is a list of the ST7 registers used by ASST7:
a - 8-bit accumulator
x,y - 8-bit index registers
cc - 8-bit condition code register
s - 16-bit stack pointer
ST7 INSTRUCTION SET
The following list specifies the format for each addressing
mode supported by ASST7:
reg register addressing
(a,x,y,s,cc)
#data immediate data byte
*saddr 8-bit zero page addressing
0x00 <= dir <= 0xFF
laddr 16-bit addressing
(x) register indirect addressing
(*sofst,r) short indexed (r = x,y)
(sofst,r).b
(lofst,r).w long indexed (r = x,y)
(ofst,r) if ofst is relocatable or
an external value then
the (lofst,r).w mode is
selected by default
else
(ofst,r) if ofst is a locally
defined constant then
the (sofst,r).b mode
is selected when
0x00 <= ofst <= 0xFF else
the (lofst,r).w mode
is selected
Instructions supporting
only a single form will
use the appropriate form
but will report an error.
[*saddr] short indirect
[saddr].b
[laddr].w long indexed
[addr] if addr is relocatable or
an external value then
the [laddr].w mode is
selected by default
else
[addr] if addr is a locally
defined constant then
the [saddr].b mode
is selected when
0x00 <= addr <= 0xFF else
the [laddr].w mode
is selected
Instructions supporting
only a single form will
use the appropriate form
but will report an error.
([*saddr],r) short indirect indexed
([saddr].b,r) (r = x,y)
([saddr],r).b
([laddr].w,r) long indirect indexed
([laddr],r).w (r = x,y)
([addr],r) if addr is relocatable or
an external value then
the ([laddr],r).w mode is
selected by default
else
([addr],r) if addr is a locally
defined constant then
the ([saddr],r).b mode
is selected when
0x00 <= addr <= 0xFF else
the ([laddr],r).w mode
is selected
Instructions supporting
only a single form will
use the appropriate form
but will report an error.
label pc-relative branch addressing
The terms data, saddr, laddr, addr, sofst, lofst, ofst, and
label may all be expressions.
Note that not all addressing modes are valid with every in-
struction, refer to the ST7 technical data for valid modes.
The following tables list all ST7 mnemonics recognized by the
ASST7 assembler. The designation [] refers to a required ad-
dressing mode argument.
Inherent Instructions
nop trap
wfi halt
ret iret
sim rim
scf rcf
rsp
Conditional Branch Instructions
jra label
jrt label jrf label
jrih label jril label
jrh label jrnh label
jrm label jrnm label
jrmi label jrpl label
jreq label jrne label
jrc label jrnc label
jrult label jruge label
jrugt label jrule label
jra [saddr]
jrt [saddr] jrf [saddr]
jrih [saddr] jril [saddr]
jrh [saddr] jrnh [saddr]
jrm [saddr] jrnm [saddr]
jrmi [saddr] jrpl [saddr]
jreq [saddr] jrne [saddr]
jrc [saddr] jrnc [saddr]
jrult [saddr] jruge [saddr]
jrugt [saddr] jrule [saddr]
Bit Test and Branch Instructions
btjt saddr,#,label
btjf saddr,#,label
btjt [saddr],#,label
btjf [saddr],#,label
Bit Manipulation Instructions
bset saddr,#
bres saddr,#
bset [saddr],#
bres [saddr],#
Single Operand Instructions
neg [] cpl []
srl [] rrc []
sra [] rlc []
sll [] sla []
dec [] inc []
tnz [] swap []
clr []
pop reg push reg
Double Operand Instructions
add a,[] adc a,[]
and a,[] bcp a,[]
or a,[] sbc a,[]
sub a,[] xor a,[]
mul x,a mul y,a
cp reg,[]
ld [],[]
Call to Subroutine and Jump Instructions
call [] jp []
callr label callr [saddr]
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Last Updated: September 2023