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authorMax Horn2009-07-14 23:03:25 +0000
committerMax Horn2009-07-14 23:03:25 +0000
commit99fc508609e0def31b9e5c7b59e28fada54c0e1e (patch)
treeeb237d9920221e0dfaf92c3ce10862d3ec91530d /engines
parent59b35ff5fbb00b47b473c8d0c5ff670bd500e347 (diff)
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AGOS: Some more cleanup and added some comments to the PN code
svn-id: r42494
Diffstat (limited to 'engines')
-rw-r--r--engines/agos/pn.cpp10
-rw-r--r--engines/agos/script_pn.cpp56
2 files changed, 42 insertions, 24 deletions
diff --git a/engines/agos/pn.cpp b/engines/agos/pn.cpp
index fd88d63ec3..d92efa9077 100644
--- a/engines/agos/pn.cpp
+++ b/engines/agos/pn.cpp
@@ -269,16 +269,16 @@ void AGOSEngine_PN::processor() {
_variableArray[16] = _quickshort[6];
_variableArray[17] = _quickshort[7];
_variableArray[19] = getptr(55L);
+
+ // q indicates the process to run and is 0 the first time,
+ // but 1 later on (i.e., when we are "called" from badload()).
setposition(q, 0);
doline(0);
}
void AGOSEngine_PN::setqptrs() {
- int a = 0;
-
- while (a < 11) {
- _quickptr[a] = getlong(3L * a);
- a++;
+ for (int i = 0; i < 11; ++i) {
+ _quickptr[i] = getlong(3 * i);
}
_quickptr[11] = getlong(58L);
_quickptr[12] = getlong(61L);
diff --git a/engines/agos/script_pn.cpp b/engines/agos/script_pn.cpp
index 9fe05f7f6a..4f9aab2965 100644
--- a/engines/agos/script_pn.cpp
+++ b/engines/agos/script_pn.cpp
@@ -30,6 +30,10 @@
namespace AGOS {
+enum {
+ kJmpClassNum = -1
+};
+
#define OPCODE(x) _OPCODE(AGOSEngine_PN, x)
void AGOSEngine_PN::setupOpcodes() {
@@ -122,7 +126,7 @@ void AGOSEngine_PN::setupOpcodes() {
void AGOSEngine_PN::executeOpcode(int opcode) {
OpcodeProcPN op = _opcodesPN[opcode].proc;
- (this->*op) ();
+ (this->*op)();
}
int AGOSEngine_PN::readfromline() {
@@ -303,11 +307,10 @@ void AGOSEngine_PN::opn_opcode21() {
void AGOSEngine_PN::opn_opcode22() {
int pf[8];
- int a;
- a = varval();
- funcentry(pf, a);
+ int n = varval();
+ funcentry(pf, n);
funccpy(pf);
- setposition(a, 0);
+ setposition(n, 0);
setScriptReturn(true);
}
@@ -316,19 +319,27 @@ void AGOSEngine_PN::opn_opcode23() {
}
void AGOSEngine_PN::opn_opcode24() {
- popstack(-1);
+ popstack(kJmpClassNum);
+ // Jump back to the last doline, which will return 2-1=1.
+ // That value then is returned to actCallD, which once again
+ // returns it. In the end, this amounts to a setScriptReturn(true)
+ // (but possibly in a different level than the current one).
longjmp(*(_stackbase->savearea), 2);
setScriptReturn(false);
}
void AGOSEngine_PN::opn_opcode25() {
- popstack(-1);
+ popstack(kJmpClassNum);
+ // Jump back to the last doline, which will return 1-1=0.
+ // That value then is returned to actCallD, which once again
+ // returns it. In the end, this amounts to a setScriptReturn(false)
+ // (but possibly in a different level than the current one).
longjmp(*(_stackbase->savearea), 1);
setScriptReturn(false);
}
void AGOSEngine_PN::opn_opcode26() {
- while ((_stackbase != NULL) && (_stackbase->classnum != -1))
+ while ((_stackbase != NULL) && (_stackbase->classnum != kJmpClassNum))
junkstack();
dumpstack();
setScriptReturn(true);
@@ -348,6 +359,8 @@ void AGOSEngine_PN::opn_opcode28() {
void AGOSEngine_PN::opn_opcode29() {
popstack(varval());
+ // Jump back to the last doline indicated by the top stackfram.
+ // The -1 tells it to simply go on with its business.
longjmp(*(_stackbase->savearea), -1);
setScriptReturn(false);
}
@@ -837,7 +850,7 @@ void AGOSEngine_PN::setbitf(uint32 ptr, int offs, int val) {
int AGOSEngine_PN::actCallD(int n) {
int pf[8];
funcentry(pf, n);
- addstack(-1);
+ addstack(kJmpClassNum);
funccpy(pf);
setposition(n, 0);
return doline(1);
@@ -862,7 +875,7 @@ int AGOSEngine_PN::doaction() {
int AGOSEngine_PN::doline(int needsave) {
int x;
- jmp_buf *ljmpbuff = NULL;
+ jmp_buf *old_jmpbuf = NULL;
jmp_buf *mybuf;
mybuf = (jmp_buf *)malloc(sizeof(jmp_buf));
@@ -874,16 +887,25 @@ int AGOSEngine_PN::doline(int needsave) {
// (and of course 0 when it returns directly, as always).
if (x > 0) {
dumpstack();
- _cjmpbuff = ljmpbuff;
+ // Restore the active jmpbuf to its previous value,
+ // then return the longjmp value (will be 2-1=1 or 1-1=0).
+ _cjmpbuff = old_jmpbuf;
free((char *)mybuf);
return (x - 1);
}
if (x == -1) {
+ // Make this doline instance the active one (again).
+ // This is used to "return" over possibly multiple
+ // layers of nested script invocations.
+ // Kind of like throwing an exception.
_cjmpbuff = mybuf;
goto carryon;
}
- ljmpbuff = _cjmpbuff;
+
+ // Remember the previous active jmpbuf (gets restored
+ // above when a longjmp with a positive param occurs).
+ old_jmpbuf = _cjmpbuff;
_cjmpbuff = mybuf;
if (needsave)
_stackbase->savearea = mybuf;
@@ -963,13 +985,9 @@ void AGOSEngine_PN::funccpy(int *store) {
}
void AGOSEngine_PN::funcentry(int *store, int procn) {
- int ct = 0;
- int nprm;
-
- nprm = _dataBase[getlong(_quickptr[6] + 3L * procn)];
- while (ct < nprm) {
+ int numParams = _dataBase[getlong(_quickptr[6] + 3 * procn)];
+ for (int i = 0; i < numParams; ++i) {
*store++ = varval();
- ct++;
}
}
@@ -1082,7 +1100,7 @@ void AGOSEngine_PN::junkstack() {
error("junkstack: Stack underflow or unknown longjmp");
a = _stackbase->nextframe;
- if (_stackbase->classnum == -1)
+ if (_stackbase->classnum == kJmpClassNum)
free((char *)_stackbase->savearea);
free((char *)_stackbase);
_stackbase = a;