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Improving some code and data distinction rules

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- If an address is unreachable it is data even if a branch crosses
- If a branch crosses data then that branch can be valid code
- If a segment is initially considered code but not reachable after all
is said and done it is reverted to data
This commit is contained in:
Carl-Henrik Skårstedt 2015-12-14 22:07:30 -08:00
parent ec01fcc6e1
commit b8362cbb0b
1 changed files with 49 additions and 18 deletions
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67
disassembler/x65dsasm.cpp
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@ -1573,7 +1573,7 @@ void GetReferences(unsigned char *mem, size_t bytes, bool acc_16, bool ind_16, i
mem += arg_size;
}
if (separator && curr_label>0 && refs[curr_label-1].data!=DT_PTRS && refs[curr_label-1].data!=DT_PTRS_DATA &&
curr!=refs[curr_label].address && !cutoff) {
curr!=refs[curr_label].address && !cutoff) {
int end_addr = curr_label<(int)refs.size() ? refs[curr_label].address : (int)(addr_orig + bytes_orig);
for (std::vector<RefAddr>::iterator k = refs.begin(); k!= refs.end(); ++k) {
std::vector<RefLink> &l = *k->pRefs;
@ -1581,7 +1581,7 @@ void GetReferences(unsigned char *mem, size_t bytes, bool acc_16, bool ind_16, i
while (r!=l.end()) {
if (r->instr_addr>=curr && r->instr_addr<end_addr) {
r = l.erase(r);
} else
} else
++r;
}
}
@ -1604,8 +1604,8 @@ void GetReferences(unsigned char *mem, size_t bytes, bool acc_16, bool ind_16, i
refs[curr_label].separator = 1; // user labels are always global
was_data = refs[curr_label].data!=DT_CODE;
} else {
bool prev_data = was_data;
was_data = separator && !(!was_data && op==0x4c && prev_op==0x4c);
bool prev_data = was_data && !cutoff;
was_data = (separator || cutoff) && !(!was_data && op==0x4c && prev_op==0x4c);
if (!prev_data) {
for (size_t j = 0; j<pRefs.size(); ++j) {
RefType type = pRefs[j].type;
@ -1669,6 +1669,7 @@ void GetReferences(unsigned char *mem, size_t bytes, bool acc_16, bool ind_16, i
was_data = refs[lbl].data != DT_CODE;
}
}
cutoff = false;
curr_label++;
}
separator = false;
@ -1700,7 +1701,7 @@ void GetReferences(unsigned char *mem, size_t bytes, bool acc_16, bool ind_16, i
prev_addr = curr;
}
int last = (int)refs.size()-1;
while (last>1 && refs[last-1].data!=DT_CODE) {
@ -1711,8 +1712,7 @@ void GetReferences(unsigned char *mem, size_t bytes, bool acc_16, bool ind_16, i
while (r != pRefs.end()) {
if (r->instr_addr>=start_addr && r->instr_addr<end_addr) {
r = pRefs.erase(r);
}
else
} else
++r;
}
}
@ -1858,6 +1858,23 @@ void GetReferences(unsigned char *mem, size_t bytes, bool acc_16, bool ind_16, i
++k;
}
}
k = refs.begin();
while (k!=refs.end()) {
if (k->data == DT_CODE && !k->label) {
std::vector<RefLink> &links = *k->pRefs;
bool definitely_code = false;
for (std::vector<RefLink>::iterator l = links.begin(); l!=links.end(); ++l) {
RefType t = l->type;
if (t==RT_BRANCH || t==RT_BRA_L || t==RT_JUMP || t==RT_JSR) {
definitely_code = true;
break;
}
}
if (!definitely_code)
k->data = DT_DATA;
}
++k;
}
}
// returns true if the instruction accessing memory can ONLY read that memory, not write back or jump to it
@ -1910,6 +1927,8 @@ void Disassemble(strref filename, unsigned char *mem, size_t bytes, bool acc_16,
opened = true;
}
int reseperate = -1;
while (bytes) {
// Determine if current address is referenced from somewhere
while (curr_label_index<(int)refs.size() && addr >= refs[curr_label_index].address) {
@ -1937,9 +1956,11 @@ void Disassemble(strref filename, unsigned char *mem, size_t bytes, bool acc_16,
int lbl_glb = lbl;
while (lbl_glb>0 && refs[lbl_glb].local)
lbl_glb--;
if (refs[lbl].label)
out.append(refs[lbl].label);
else {
if (refs[lbl_glb].label) {
out.append(' ');
out.append(refs[lbl_glb].label);
out.append(" /");
} else {
RefAddr &ra = refs[lbl_glb];
out.sprintf_append(" %s_%d /", ra.local ? ".l" : (ra.data==DT_CODE ? "Code" : (ra.address>=0 && ra.address<0x100 ? "zp" : "Data")), ra.number);
}
@ -1976,6 +1997,7 @@ void Disassemble(strref filename, unsigned char *mem, size_t bytes, bool acc_16,
is_data = !!ref.data;
is_ptrs = is_data && (ref.data==DT_PTRS || ref.data==DT_PTRS_DATA);
separator = false;
reseperate = -1;
curr_label_index++;
}
if (src && (is_data || separator)) {
@ -1983,7 +2005,12 @@ void Disassemble(strref filename, unsigned char *mem, size_t bytes, bool acc_16,
int left = end_addr - addr;
if (curr_label_index<(int)refs.size() && refs[curr_label_index].address<end_addr)
left = refs[curr_label_index].address - addr;
is_data = true;
if (addr<reseperate && (left+addr)>reseperate && !is_data)
left = reseperate - addr;
else
is_data = true;
reseperate = -1;
separator = false;
if (is_ptrs) {
int blk = refs[curr_label_index-1].size ? refs[curr_label_index-1].size : left;
while (left>=2 && bytes>=2 && blk) {
@ -2086,14 +2113,18 @@ void Disassemble(strref filename, unsigned char *mem, size_t bytes, bool acc_16,
std::vector<RefLink> &pRefs = *refs[i].pRefs;
if (refs[i].address<=curr_addr) {
for (size_t j = 0; j<pRefs.size() && separator; ++j) {
if (pRefs[j].type == RT_BRANCH && pRefs[j].instr_addr>curr_addr)
separator = false;
}
} else {
for (size_t j = 0; j<pRefs.size() && separator; ++j) {
if (pRefs[j].type == RT_BRANCH && pRefs[j].instr_addr<curr_addr)
separator = false;
if (pRefs[j].type == RT_BRANCH && pRefs[j].instr_addr>curr_addr) {
if (refs[i].address==addr)
separator = false;
else if (reseperate<0 || pRefs[j].instr_addr<reseperate)
reseperate = pRefs[j].instr_addr;
}
}
// } else {
// for (size_t j = 0; j<pRefs.size() && separator; ++j) {
// if (pRefs[j].type == RT_BRANCH && pRefs[j].instr_addr<curr_addr)
// separator = false;
// }
}
}
}