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Improved documentation & AVR8 cref
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@Arakula
Arakula authored Jan 27, 2021
1 parent a7106f9 commit 8e4f16f
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Showing 3 changed files with 70 additions and 37 deletions.
8 changes: 3 additions & 5 deletions DasmAvr8.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1274,7 +1274,7 @@ for (i = 0; i < numOperands; i++)
// if this is relative, make sure a label for the relation is there
MemAttributeAvr8::RelType rt = GetRelative(addr, rel, relBus, bus);
if (rt != MemAttributeAvr8::RelUntyped)
AddLabel(rel, relBus ? Data : Code, "", true, relBus);
AddRelativeLabel(rel, addr, relBus ? Data : Code, true, relBus, addr);

Label *lbl = SetDefLabelUsed(addr, bus);
if (lbl)
Expand All @@ -1288,15 +1288,13 @@ for (i = 0; i < numOperands; i++)
case OpndLongAbsAddrData:
bus = (mnemo[ii->mnemonic].memType != Code) ? BusData : BusCode;
if (!IsConst(addr, BusData /*bus*/))
AddLabel(operand, mnemo[ii->mnemonic].memType, "", true,
bus);
AddRelativeLabel(operand, addr, mnemo[ii->mnemonic].memType, true, bus, addr);
break;
case OpndBranchAddr:
case OpndRelAddr:
bus = (mnemo[ii->mnemonic].memType != Code) ? BusData : BusCode;
if (!IsConst(addr, bus))
AddLabel(operand + addr + 2, mnemo[ii->mnemonic].memType, "", true,
bus);
AddRelativeLabel(operand + addr + 2, addr, mnemo[ii->mnemonic].memType, true, bus, addr);
break;
default:
break;
Expand Down
9 changes: 5 additions & 4 deletions dasmfw.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1866,13 +1866,14 @@ do
string item = value.substr(0, idx);
value = (idx >= value.size()) ? "" : trim(value.substr(idx));
to = 0;
MemoryType memtype = (infoBus == BusCode) ? Code : Data;
switch (cmdType)
{
case infoPatch : /* PATCH addr [byte]* */
if (sscanf(item.c_str(), "%x", &to) == 1)
{
if (pDasm->GetMemIndex(from, infoBus) == NO_ADDRESS)
pDasm->AddMemory(from, 1, Code, NULL, infoBus);
pDasm->AddMemory(from, 1, memtype, NULL, infoBus);
pDasm->SetUByte(from, (uint8_t)to, infoBus);
from += step;
}
Expand All @@ -1883,7 +1884,7 @@ do
if (sscanf(item.c_str(), "%x", &to) == 1)
{
if (pDasm->GetMemIndex(from, infoBus) == NO_ADDRESS)
pDasm->AddMemory(from, 2, Data, NULL, infoBus);
pDasm->AddMemory(from, 2, memtype, NULL, infoBus);
pDasm->SetUWord(from, (uint16_t)to, infoBus);
from += (step > 2) ? step : 2;
}
Expand All @@ -1894,7 +1895,7 @@ do
if (sscanf(item.c_str(), "%x", &to) == 1)
{
if (pDasm->GetMemIndex(from, infoBus) == NO_ADDRESS)
pDasm->AddMemory(from, 4, Data, NULL, infoBus);
pDasm->AddMemory(from, 4, memtype, NULL, infoBus);
pDasm->SetUDWord(from, (uint32_t)to, infoBus);
from += (step > 4) ? step : 4;
}
Expand All @@ -1909,7 +1910,7 @@ do
int sz;
if (pDasm->GetMemIndex(from, infoBus) == NO_ADDRESS)
{
pDasm->AddMemory(from, 4, Data, NULL, infoBus);
pDasm->AddMemory(from, 4, memtype, NULL, infoBus);
sz = 4;
}
else
Expand Down
90 changes: 62 additions & 28 deletions dasmfw.htm
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Original file line number Diff line number Diff line change
Expand Up @@ -346,6 +346,17 @@ <h3>Info File Instructions</h3>
<pre>from[-to[/step]]</pre>
<p>where not all instructions need each part. The step size, if needed and not given, defaults to 1.
</p>
<p><i><b>Note:</b></i> wherever <i><b>text</b></i> requires leading blanks or tabs,
it isn't possible to simply put them into the instruction, as dasmfw would discard them.
For these cases, simply prepend a '\' (backslash) to the text, like, for example, in<br />
<b>insert 0 \&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;OPT H63</b><br />
so that dasmfw knows where <i><b>text</b></i> really starts.
Despite the similarity, dasmfw doesn't know the range of "C" escape characters; a '\'
simply means "Ignore this backslash, but make sure the next character is part of the text".
If you need to have a <b>*</b> as part of the text, it is mandatory to write it as <b>\*</b>;
dasmfw would otherwise assume the line ends at the <b>*</b>, which starts the comment part.
</p>

<h3>Global Info File Instructions</h3>

<dl>
Expand Down Expand Up @@ -472,12 +483,14 @@ <h3>Global Info File Instructions</h3>
<dd>Removes the <b>forceaddr</b> (see above) flag for the given range.</dd>
</dl>
<dl>
<dt><b>label <i>addr name</i></b></dt>
<dt><b>label <i>addr[-addr] name</i></b></dt>
<dd>sets a label at the given address.<br />
Note that dasmfw doesn't restrict the length of the label, nor does it enforce
a given range of characters (except for * and zero bytes - these terminate
the name). This may conflict with the assembler of your choice, so choose
the labels with caution.</dd>
the labels with caution.<br />
If a range is given, dasmfw automatically appends "+1","+2",&hellip; for the
successive positions.</dd>

<dt><b>used[label] <i>addr [name]</i></b></dt>
<dd>forces the given address used.<br />
Expand Down Expand Up @@ -656,6 +669,10 @@ <h3>Disassembler-specific Info File Instructions</h3>
removes <i>setdp</i> effects from the given range or, if no range is given,
sets the global direct page back to the default.</dd>
</dl>
<p>The Atmel AVR8 codeset and the underlying philosophy has some peculiarities. One of these is
that addresses of data have to be loaded into registers in two steps: one for the high byte of
the address, one for the low byte. The various <b>high</b> and <b>low</b>
statements described below reflect that fact.</p>
<dl>
<dt><b>reglabel <i>addr Rxx [text]</i></b></dt>
<dd>AVR8 only<br />
Expand All @@ -665,36 +682,53 @@ <h3>Disassembler-specific Info File Instructions</h3>
<dt><b>unreglabel <i>addr Rxx</i></b></dt>
<dd>AVR8 only<br />
Cancels the previous reglabel definition for the passed register.</dd>
<dt><b>high <i>[bus tgtbus] addr[-addr] addr</i></b></dt>
<dd>AVR8 only<br />
TODO (... I should document things like that immediately, not years later! :-)</dd>
<dt><b>low <i>[bus tgtbus] addr[-addr] addr</i></b></dt>
<dd>AVR8 only<br />
TODO</dd>
<dt><b>mhigh <i>[bus tgtbus] addr[-addr] addr</i></b></dt>
<dt><b>high <i>[bus tgtbus] addr[-addr] reladdr</i></b><br />
<b>low <i>[bus tgtbus] addr[-addr] reladdr</i></b></dt>
<dd>AVR8 only<br />
TODO</dd>
<dt><b>mlow <i>[bus tgtbus] addr[-addr] addr</i></b></dt>
<dd>AVR8 only<br />
TODO</dd>
<dt><b>high2 <i>[bus tgtbus] addr[-addr] addr</i></b></dt>
These statements innstruct dasmfw to treat the value in the instruction as the low
or high part of the address given in reladdr. As an example, if you come across a
code passage like
<pre> ldi R26,0x00 ; 000634: A0 E0 '..'
ldi R27,0x01 ; 000636: B1 E0</pre> and you know that R26:27 is
a pointer to a data item, it's easy to determine that this sets up the pointer to
0x0100. In this case, adding the statements
<pre>low bus data 0634 0100
high bus data 0636 0100</pre>
would lead to the following, much more readable output:
<pre> ldi R26,LOW(MD0100)
ldi R27,HIGH(MD0100)</pre>
</dd>
<dt><b>mhigh <i>[bus tgtbus] addr[-addr] reladdr</i></b><br />
<b>mlow <i>[bus tgtbus] addr[-addr] reladdr</i></b></dt>
<dd>AVR8 only<br />
TODO</dd>
<dt><b>low2 <i>[bus tgtbus] addr[-addr] addr</i></b></dt>
avr-gcc has a tendency to produce code like the following:
<pre> subi R30,0xae ; 001764: EE 5A
sbci R31,0xfe ; 001766: FE 4F</pre>
That means: it subtracts the negated address parts from the registers.
Why ... I don't know. Someone decided that optimizing code this way was
a good idea. Now, this would require the use of a calculator (or mental artistry
for hex wizards) to find out what address is hidden behind the constant 0xfeae
that's subtracted from the pointer. dasmfw makes that a bit easier; adding the
statements <pre>mlow bus data 1764 feae
mhigh bus data 1766 feae</pre> leads to the much more pleasing output <pre>
subi R30,LOW(-MD0152)
sbci R31,HIGH(-MD0152)</pre></dd>
<dt><b>high2 <i>[bus tgtbus] addr[-addr] reladdr</i></b><br />
<b>low2 <i>[bus tgtbus] addr[-addr] reladdr</i></b></dt>
<dd>AVR8 only<br />
TODO</dd>
Works like low/high, but for pointers into the <i>code</i> area - the AVR8 instruction
set addresses the code area in words, so pointers have to be set to half the real value.
So, if you come across something like that:
<pre> ldi R16,0xaf ; 0006D0: 0F EA
ldi R17,0x03 ; 0006D2: 13 E0</pre>
and you know that R16:17 is used as a pointer into the code area, adding the statements
<pre>low2 06d0 03af
high2 06d2 03af</pre> would lead to the output
<pre> ldi R16,LOW(Z00075E>>1)
ldi R17,HIGH(Z00075E>>1)</pre>
which shows the <i>real</i> address pointed to.
</dd>
</dl>

<p><i><b>Note:</b></i> wherever <i><b>text</b></i> requires leading blanks or tabs,
it isn't possible to simply put them into the instruction, as dasmfw would discard them.
For these cases, simply prepend a '\' (backslash) to the text, like, for example, in<br />
<b>insert 0 \&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;OPT H63</b><br />
so that dasmfw knows where <i><b>text</b></i> really starts.
Despite the similarity, dasmfw doesn't know the range of "C" escape characters; a '\'
simply means "Ignore this backslash, but make sure the next character is part of the text".
If you need to have a <b>*</b> as part of the text, it is mandatory to write it as <b>\*</b>;
dasmfw would otherwise assume the line ends at the <b>*</b>, which starts the comment part.
</p>

</body>
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