/* */
/* */
/* */
-/* (C) 2001 Ullrich von Bassewitz */
-/* Wacholderweg 14 */
-/* D-70597 Stuttgart */
-/* EMail: uz@cc65.org */
+/* (C) 2001-2006, Ullrich von Bassewitz */
+/* Römerstrasse 52 */
+/* D-70794 Filderstadt */
+/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* common */
#include "chartype.h"
#include "check.h"
+#include "debugflag.h"
#include "global.h"
#include "hashstr.h"
+#include "strbuf.h"
#include "strutil.h"
#include "xmalloc.h"
-#include "xsprintf.h"
/* cc65 */
#include "asmlabel.h"
#include "codeent.h"
#include "codeinfo.h"
+#include "codeseg.h"
#include "datatype.h"
#include "error.h"
+#include "global.h"
+#include "ident.h"
#include "symentry.h"
-#include "codeseg.h"
+static void CS_PrintFunctionHeader (const CodeSeg* S, FILE* F)
+/* Print a comment with the function signature to the given file */
+{
+ /* Get the associated function */
+ const SymEntry* Func = S->Func;
+
+ /* If this is a global code segment, do nothing */
+ if (Func) {
+ fprintf (F,
+ "; ---------------------------------------------------------------\n"
+ "; ");
+ PrintFuncSig (F, Func->Name, Func->Type);
+ fprintf (F,
+ "\n"
+ "; ---------------------------------------------------------------\n"
+ "\n");
+ }
+}
+
+
+
static void CS_MoveLabelsToEntry (CodeSeg* S, CodeEntry* E)
/* Move all labels from the label pool to the given entry and remove them
* from the pool.
-static CodeLabel* CS_AddLabelInternal (CodeSeg* S, const char* Name,
- void (*ErrorFunc) (const char*, ...))
-/* Add a code label for the next instruction to follow */
-{
- /* Calculate the hash from the name */
- unsigned Hash = HashStr (Name) % CS_LABEL_HASH_SIZE;
-
- /* Try to find the code label if it does already exist */
- CodeLabel* L = CS_FindLabel (S, Name, Hash);
-
- /* Did we find it? */
- if (L) {
- /* We found it - be sure it does not already have an owner */
- if (L->Owner) {
- ErrorFunc ("ASM label `%s' is already defined", Name);
- }
- } else {
- /* Not found - create a new one */
- L = CS_NewCodeLabel (S, Name, Hash);
- }
-
- /* Safety. This call is quite costly, but safety is better */
- if (CollIndex (&S->Labels, L) >= 0) {
- ErrorFunc ("ASM label `%s' is already defined", Name);
- }
-
- /* We do now have a valid label. Remember it for later */
- CollAppend (&S->Labels, L);
-
- /* Return the label */
- return L;
-}
-
-
-
/*****************************************************************************/
/* Functions for parsing instructions */
/*****************************************************************************/
* white space, for example.
*/
{
- char Mnemo[64];
- const OPCDesc* OPC;
- am_t AM = 0; /* Initialize to keep gcc silent */
- char Arg[64];
+ char Mnemo[IDENTSIZE+10];
+ const OPCDesc* OPC;
+ am_t AM = 0; /* Initialize to keep gcc silent */
+ char Arg[IDENTSIZE+10];
char Reg;
CodeEntry* E;
- CodeLabel* Label;
+ CodeLabel* Label;
/* Read the first token and skip white space after it */
L = SkipSpace (ReadToken (L, " \t:", Mnemo, sizeof (Mnemo)));
L = SkipSpace (L+1);
/* Add the label */
- CS_AddLabelInternal (S, Mnemo, Error);
+ CS_AddLabel (S, Mnemo);
/* If we have reached end of line, bail out, otherwise a mnemonic
* may follow.
switch (*L) {
case '\0':
- /* Implicit */
- AM = AM65_IMP;
+ /* Implicit or accu */
+ if (OPC->Info & OF_NOIMP) {
+ AM = AM65_ACC;
+ } else {
+ AM = AM65_IMP;
+ }
break;
case '#':
AM = AM65_ZPX;
} else {
AM = AM65_ABSX;
- }
+ }
} else if (Reg == 'Y') {
AM = AM65_ABSY;
} else {
/* Create a new code segment, initialize and return it */
{
unsigned I;
- const type* RetType;
+ const Type* RetType;
/* Allocate memory */
CodeSeg* S = xmalloc (sizeof (CodeSeg));
S->ExitRegs = REG_NONE;
}
+ /* Copy the global optimization settings */
+ S->Optimize = (unsigned char) IS_Get (&Optimize);
+ S->CodeSizeFactor = (unsigned) IS_Get (&CodeSizeFactor);
+
/* Return the new struct */
return S;
}
{
const char* L;
CodeEntry* E;
- char Token[64];
+ char Token[IDENTSIZE+10];
/* Format the line */
- char Buf [256];
- xvsprintf (Buf, sizeof (Buf), Format, ap);
+ StrBuf Buf = STATIC_STRBUF_INITIALIZER;
+ SB_VPrintf (&Buf, Format, ap);
/* Skip whitespace */
- L = SkipSpace (Buf);
+ L = SkipSpace (SB_GetConstBuf (&Buf));
/* Check which type of instruction we have */
- E = 0; /* Assume no insn created */
+ E = 0; /* Assume no insn created */
switch (*L) {
case '\0':
if (E) {
CS_AddEntry (S, E);
}
+
+ /* Cleanup the string buffer */
+ DoneStrBuf (&Buf);
}
/* Delete an entry from the code segment. This includes moving any associated
* labels, removing references to labels and even removing the referenced labels
* if the reference count drops to zero.
+ * Note: Labels are moved forward if possible, that is, they are moved to the
+ * next insn (not the preceeding one).
*/
{
/* Get the code entry for the given index */
+int CS_RangeHasLabel (CodeSeg* S, unsigned Start, unsigned Count)
+/* Return true if any of the code entries in the given range has a label
+ * attached. If the code segment does not span the given range, check the
+ * possible span instead.
+ */
+{
+ unsigned EntryCount = CS_GetEntryCount(S);
+
+ /* Adjust count. We expect at least Start to be valid. */
+ CHECK (Start < EntryCount);
+ if (Start + Count > EntryCount) {
+ Count = EntryCount - Start;
+ }
+
+ /* Check each entry. Since we have validated the index above, we may
+ * use the unchecked access function in the loop which is faster.
+ */
+ while (Count--) {
+ const CodeEntry* E = CollAtUnchecked (&S->Entries, Start++);
+ if (CE_HasLabel (E)) {
+ return 1;
+ }
+ }
+
+ /* No label in the complete range */
+ return 0;
+}
+
+
+
CodeLabel* CS_AddLabel (CodeSeg* S, const char* Name)
/* Add a code label for the next instruction to follow */
{
- return CS_AddLabelInternal (S, Name, Internal);
+ /* Calculate the hash from the name */
+ unsigned Hash = HashStr (Name) % CS_LABEL_HASH_SIZE;
+
+ /* Try to find the code label if it does already exist */
+ CodeLabel* L = CS_FindLabel (S, Name, Hash);
+
+ /* Did we find it? */
+ if (L) {
+ /* We found it - be sure it does not already have an owner */
+ if (L->Owner) {
+ Error ("ASM label `%s' is already defined", Name);
+ return L;
+ }
+ } else {
+ /* Not found - create a new one */
+ L = CS_NewCodeLabel (S, Name, Hash);
+ }
+
+ /* Safety. This call is quite costly, but safety is better */
+ if (CollIndex (&S->Labels, L) >= 0) {
+ Error ("ASM label `%s' is already defined", Name);
+ return L;
+ }
+
+ /* We do now have a valid label. Remember it for later */
+ CollAppend (&S->Labels, L);
+
+ /* Return the label */
+ return L;
}
/* Get the insn referencing this label */
CodeEntry* E = CollAt (&L->JumpFrom, I);
/* Remove the reference */
- E->JumpTo = 0;
+ CE_ClearJumpTo (E);
}
CollDeleteAll (&L->JumpFrom);
*/
{
unsigned I;
+ unsigned J;
/* First, remove all labels from the label symbol table that don't have an
* owner (this means that they are actually external labels but we didn't
CodeLabel** L = &S->LabelHash[I];
while (*L) {
if ((*L)->Owner == 0) {
- /* The label does not have an owner, remove it from the chain */
+
+ /* The label does not have an owner, remove it from the chain */
CodeLabel* X = *L;
*L = X->Next;
+
+ /* Cleanup any entries jumping to this label */
+ for (J = 0; J < CL_GetRefCount (X); ++J) {
+ /* Get the entry referencing this label */
+ CodeEntry* E = CL_GetRef (X, J);
+ /* And remove the reference. Do NOT call CE_ClearJumpTo
+ * here, because this will also clear the label name,
+ * which is not what we want.
+ */
+ E->JumpTo = 0;
+ }
+
+ /* Print some debugging output */
if (Debug) {
printf ("Removing unused global label `%s'", X->Name);
}
+
+ /* And free the label */
FreeCodeLabel (X);
} else {
/* Label is owned, point to next code label pointer */
CollDeleteItem (&L->JumpFrom, E);
/* The entry jumps no longer to L */
- E->JumpTo = 0;
+ CE_ClearJumpTo (E);
/* If there are no more references, delete the label */
if (CollCount (&L->JumpFrom) == 0) {
-void CS_Output (const CodeSeg* S, FILE* F)
+void CS_ResetMarks (CodeSeg* S, unsigned First, unsigned Last)
+/* Remove all user marks from the entries in the given range */
+{
+ while (First <= Last) {
+ CE_ResetMark (CS_GetEntry (S, First++));
+ }
+}
+
+
+
+int CS_IsBasicBlock (CodeSeg* S, unsigned First, unsigned Last)
+/* Check if the given code segment range is a basic block. That is, check if
+ * First is the only entrance and Last is the only exit. This means that no
+ * jump/branch inside the block may jump to an insn below First or after(!)
+ * Last, and that no insn may jump into this block from the outside.
+ */
+{
+ unsigned I;
+
+ /* Don't accept invalid ranges */
+ CHECK (First <= Last);
+
+ /* First pass: Walk over the range and remove all marks from the entries */
+ CS_ResetMarks (S, First, Last);
+
+ /* Second pass: Walk over the range checking all labels. Note: There may be
+ * label on the first insn which is ok.
+ */
+ I = First + 1;
+ while (I <= Last) {
+
+ /* Get the next entry */
+ CodeEntry* E = CS_GetEntry (S, I);
+
+ /* Check if this entry has one or more labels, if so, check which
+ * entries jump to this label.
+ */
+ unsigned LabelCount = CE_GetLabelCount (E);
+ unsigned LabelIndex;
+ for (LabelIndex = 0; LabelIndex < LabelCount; ++LabelIndex) {
+
+ /* Get this label */
+ CodeLabel* L = CE_GetLabel (E, LabelIndex);
+
+ /* Walk over all entries that jump to this label. Check for each
+ * of the entries if it is out of the range.
+ */
+ unsigned RefCount = CL_GetRefCount (L);
+ unsigned RefIndex;
+ for (RefIndex = 0; RefIndex < RefCount; ++RefIndex) {
+
+ /* Get the code entry that jumps here */
+ CodeEntry* Ref = CL_GetRef (L, RefIndex);
+
+ /* Walk over out complete range and check if we find the
+ * refering entry. This is cheaper than using CS_GetEntryIndex,
+ * because CS_GetEntryIndex will search the complete code
+ * segment and not just our range.
+ */
+ unsigned J;
+ for (J = First; J <= Last; ++J) {
+ if (Ref == CS_GetEntry (S, J)) {
+ break;
+ }
+ }
+ if (J > Last) {
+ /* We did not find the entry. This means that the jump to
+ * out code segment entry E came from outside the range,
+ * which in turn means that the given range is not a basic
+ * block.
+ */
+ CS_ResetMarks (S, First, Last);
+ return 0;
+ }
+
+ /* If we come here, we found the entry. Mark it, so we know
+ * that the branch to the label is in range.
+ */
+ CE_SetMark (Ref);
+ }
+ }
+
+ /* Next entry */
+ ++I;
+ }
+
+ /* Third pass: Walk again over the range and check all branches. If we
+ * find a branch that is not marked, its target is not inside the range
+ * (since we checked all the labels in the range before).
+ */
+ I = First;
+ while (I <= Last) {
+
+ /* Get the next entry */
+ CodeEntry* E = CS_GetEntry (S, I);
+
+ /* Check if this is a branch and if so, if it has a mark */
+ if (E->Info & (OF_UBRA | OF_CBRA)) {
+ if (!CE_HasMark (E)) {
+ /* No mark means not a basic block. Before bailing out, be sure
+ * to remove the marks from the remaining entries.
+ */
+ CS_ResetMarks (S, I+1, Last);
+ return 0;
+ }
+
+ /* Remove the mark */
+ CE_ResetMark (E);
+ }
+
+ /* Next entry */
+ ++I;
+ }
+
+ /* Done - this is a basic block */
+ return 1;
+}
+
+
+
+void CS_OutputPrologue (const CodeSeg* S, FILE* F)
+/* If the given code segment is a code segment for a function, output the
+ * assembler prologue into the file. That is: Output a comment header, switch
+ * to the correct segment and enter the local function scope. If the code
+ * segment is global, do nothing.
+ */
+{
+ /* Get the function associated with the code segment */
+ SymEntry* Func = S->Func;
+
+ /* If the code segment is associated with a function, print a function
+ * header and enter a local scope. Be sure to switch to the correct
+ * segment before outputing the function label.
+ */
+ if (Func) {
+ /* Get the function descriptor */
+ const FuncDesc* D = GetFuncDesc (Func->Type);
+ CS_PrintFunctionHeader (S, F);
+ fprintf (F, ".segment\t\"%s\"\n\n.proc\t_%s", S->SegName, Func->Name);
+ if (D->Flags & FD_NEAR) {
+ fputs (": near", F);
+ } else if (D->Flags & FD_FAR) {
+ fputs (": far", F);
+ }
+ fputs ("\n\n", F);
+ }
+
+}
+
+
+
+void CS_OutputEpilogue (const CodeSeg* S, FILE* F)
+/* If the given code segment is a code segment for a function, output the
+ * assembler epilogue into the file. That is: Close the local function scope.
+ */
+{
+ if (S->Func) {
+ fputs ("\n.endproc\n\n", F);
+ }
+}
+
+
+
+void CS_Output (CodeSeg* S, FILE* F)
/* Output the code segment data to a file */
{
unsigned I;
return;
}
+ /* Generate register info */
+ CS_GenRegInfo (S);
+
/* Output the segment directive */
fprintf (F, ".segment\t\"%s\"\n\n", S->SegName);
- /* If this is a segment for a function, enter a function */
- if (S->Func) {
- fprintf (F, ".proc\t_%s\n\n", S->Func->Name);
- }
-
/* Output all entries, prepended by the line information if it has changed */
LI = 0;
for (I = 0; I < Count; ++I) {
/* Line info has changed, remember the new line info */
LI = E->LI;
- /* Add the source line as a comment */
+ /* Add the source line as a comment. Beware: When line continuation
+ * was used, the line may contain newlines.
+ */
if (AddSource) {
- fprintf (F, ";\n; %s\n;\n", LI->Line);
+ const char* L = LI->Line;
+ fputs (";\n; ", F);
+ while (*L) {
+ if (*L == '\n') {
+ fputs ("\n; ", F);
+ } else {
+ fputc (*L, F);
+ }
+ ++L;
+ }
+ fputs ("\n;\n", F);
}
/* Add line debug info */
if (DebugInfo) {
fprintf (F, "\t.dbg\tline, \"%s\", %u\n",
- GetInputName (LI), GetInputLine (LI));
+ GetInputName (LI), GetInputLine (LI));
}
}
/* Output the code */
/* If debug info is enabled, terminate the last line number information */
if (DebugInfo) {
- fprintf (F, "\t.dbg\tline\n");
+ fputs ("\t.dbg\tline\n", F);
}
- /* If this is a segment for a function, leave the function */
- if (S->Func) {
- fprintf (F, "\n.endproc\n\n");
- }
+ /* Free register info */
+ CS_FreeRegInfo (S);
}
RegContents Regs; /* Initial register contents */
RegContents* CurrentRegs; /* Current register contents */
int WasJump; /* True if last insn was a jump */
+ int Done; /* All runs done flag */
/* Be sure to delete all register infos */
CS_FreeRegInfo (S);
- /* On entry, the register contents are unknown */
- RC_Invalidate (&Regs);
- CurrentRegs = &Regs;
+ /* We may need two runs to get back references right */
+ do {
- /* First pass. Walk over all insns and note just the changes from one
- * insn to the next one.
- */
- WasJump = 0;
- for (I = 0; I < CS_GetEntryCount (S); ++I) {
-
- CodeEntry* P;
+ /* Assume we're done after this run */
+ Done = 1;
- /* Get the next instruction */
- CodeEntry* E = CollAtUnchecked (&S->Entries, I);
+ /* On entry, the register contents are unknown */
+ RC_Invalidate (&Regs);
+ CurrentRegs = &Regs;
- /* If the instruction has a label, we need some special handling */
- unsigned LabelCount = CE_GetLabelCount (E);
- if (LabelCount > 0) {
-
- /* Loop over all entry points that jump here. If these entry
- * points already have register info, check if all values are
- * known and identical. If all values are identical, and the
- * preceeding instruction was not an unconditional branch, check
- * if the register value on exit of the preceeding instruction
- * is also identical. If all these values are identical, the
- * value of a register is known, otherwise it is unknown.
- */
- CodeLabel* Label = CE_GetLabel (E, 0);
- unsigned Entry;
- if (WasJump) {
- /* Preceeding insn was an unconditional branch */
- CodeEntry* J = CL_GetRef(Label, 0);
- if (J->RI) {
- Regs = J->RI->Out2;
+ /* Walk over all insns and note just the changes from one insn to the
+ * next one.
+ */
+ WasJump = 0;
+ for (I = 0; I < CS_GetEntryCount (S); ++I) {
+
+ CodeEntry* P;
+
+ /* Get the next instruction */
+ CodeEntry* E = CollAtUnchecked (&S->Entries, I);
+
+ /* If the instruction has a label, we need some special handling */
+ unsigned LabelCount = CE_GetLabelCount (E);
+ if (LabelCount > 0) {
+
+ /* Loop over all entry points that jump here. If these entry
+ * points already have register info, check if all values are
+ * known and identical. If all values are identical, and the
+ * preceeding instruction was not an unconditional branch, check
+ * if the register value on exit of the preceeding instruction
+ * is also identical. If all these values are identical, the
+ * value of a register is known, otherwise it is unknown.
+ */
+ CodeLabel* Label = CE_GetLabel (E, 0);
+ unsigned Entry;
+ if (WasJump) {
+ /* Preceeding insn was an unconditional branch */
+ CodeEntry* J = CL_GetRef(Label, 0);
+ if (J->RI) {
+ Regs = J->RI->Out2;
+ } else {
+ RC_Invalidate (&Regs);
+ }
+ Entry = 1;
} else {
- RC_Invalidate (&Regs);
+ Regs = *CurrentRegs;
+ Entry = 0;
}
- Entry = 1;
- } else {
- Regs = *CurrentRegs;
- Entry = 0;
- }
- while (Entry < CL_GetRefCount (Label)) {
- /* Get this entry */
- CodeEntry* J = CL_GetRef (Label, Entry);
- if (J->RI == 0) {
- /* No register info for this entry, bail out */
- RC_Invalidate (&Regs);
- break;
- }
- if (J->RI->Out2.RegA != Regs.RegA) {
- Regs.RegA = -1;
- }
- if (J->RI->Out2.RegX != Regs.RegX) {
- Regs.RegX = -1;
- }
- if (J->RI->Out2.RegY != Regs.RegY) {
- Regs.RegY = -1;
- }
- if (J->RI->Out2.SRegLo != Regs.SRegLo) {
- Regs.SRegLo = -1;
- }
- if (J->RI->Out2.SRegHi != Regs.SRegHi) {
- Regs.SRegHi = -1;
+ while (Entry < CL_GetRefCount (Label)) {
+ /* Get this entry */
+ CodeEntry* J = CL_GetRef (Label, Entry);
+ if (J->RI == 0) {
+ /* No register info for this entry. This means that the
+ * instruction that jumps here is at higher addresses and
+ * the jump is a backward jump. We need a second run to
+ * get the register info right in this case. Until then,
+ * assume unknown register contents.
+ */
+ Done = 0;
+ RC_Invalidate (&Regs);
+ break;
+ }
+ if (J->RI->Out2.RegA != Regs.RegA) {
+ Regs.RegA = UNKNOWN_REGVAL;
+ }
+ if (J->RI->Out2.RegX != Regs.RegX) {
+ Regs.RegX = UNKNOWN_REGVAL;
+ }
+ if (J->RI->Out2.RegY != Regs.RegY) {
+ Regs.RegY = UNKNOWN_REGVAL;
+ }
+ if (J->RI->Out2.SRegLo != Regs.SRegLo) {
+ Regs.SRegLo = UNKNOWN_REGVAL;
+ }
+ if (J->RI->Out2.SRegHi != Regs.SRegHi) {
+ Regs.SRegHi = UNKNOWN_REGVAL;
+ }
+ if (J->RI->Out2.Tmp1 != Regs.Tmp1) {
+ Regs.Tmp1 = UNKNOWN_REGVAL;
+ }
+ ++Entry;
}
- ++Entry;
- }
- /* Use this register info */
- CurrentRegs = &Regs;
+ /* Use this register info */
+ CurrentRegs = &Regs;
- }
+ }
- /* Generate register info for this instruction */
- CE_GenRegInfo (E, CurrentRegs);
+ /* Generate register info for this instruction */
+ CE_GenRegInfo (E, CurrentRegs);
- /* Remember for the next insn if this insn was an uncondition branch */
- WasJump = (E->Info & OF_UBRA) != 0;
+ /* Remember for the next insn if this insn was an uncondition branch */
+ WasJump = (E->Info & OF_UBRA) != 0;
- /* Output registers for this insn are input for the next */
- CurrentRegs = &E->RI->Out;
+ /* Output registers for this insn are input for the next */
+ CurrentRegs = &E->RI->Out;
- /* If this insn is a branch on zero flag, we may have more info on
- * register contents for one of both flow directions, but only if
- * there is a previous instruction.
- */
- if ((E->Info & OF_ZBRA) != 0 && (P = CS_GetPrevEntry (S, I)) != 0) {
-
- /* Get the branch condition */
- bc_t BC = GetBranchCond (E->OPC);
-
- /* Check the previous instruction */
- switch (P->OPC) {
-
- case OP65_ADC:
- case OP65_AND:
- case OP65_DEA:
- case OP65_EOR:
- case OP65_INA:
- case OP65_LDA:
- case OP65_ORA:
- case OP65_PLA:
- case OP65_SBC:
- /* A is zero in one execution flow direction */
- if (BC == BC_EQ) {
- E->RI->Out2.RegA = 0;
- } else {
- E->RI->Out.RegA = 0;
- }
- break;
-
- case OP65_CMP:
- /* If this is an immidiate compare, the A register has
- * the value of the compare later.
- */
- if (CE_KnownImm (P)) {
- if (BC == BC_EQ) {
- E->RI->Out2.RegA = (unsigned char)P->Num;
- } else {
- E->RI->Out.RegA = (unsigned char)P->Num;
- }
- }
- break;
-
- case OP65_CPX:
- /* If this is an immidiate compare, the X register has
- * the value of the compare later.
- */
- if (CE_KnownImm (P)) {
- if (BC == BC_EQ) {
- E->RI->Out2.RegX = (unsigned char)P->Num;
- } else {
- E->RI->Out.RegX = (unsigned char)P->Num;
- }
- }
- break;
-
- case OP65_CPY:
- /* If this is an immidiate compare, the Y register has
- * the value of the compare later.
- */
- if (CE_KnownImm (P)) {
- if (BC == BC_EQ) {
- E->RI->Out2.RegY = (unsigned char)P->Num;
- } else {
- E->RI->Out.RegY = (unsigned char)P->Num;
- }
- }
- break;
-
- case OP65_DEX:
- case OP65_INX:
- case OP65_LDX:
- case OP65_PLX:
- /* X is zero in one execution flow direction */
- if (BC == BC_EQ) {
- E->RI->Out2.RegX = 0;
- } else {
- E->RI->Out.RegX = 0;
- }
- break;
-
- case OP65_DEY:
- case OP65_INY:
- case OP65_LDY:
- case OP65_PLY:
- /* X is zero in one execution flow direction */
- if (BC == BC_EQ) {
- E->RI->Out2.RegY = 0;
- } else {
- E->RI->Out.RegY = 0;
- }
- break;
-
- case OP65_TAX:
- case OP65_TXA:
- /* If the branch is a beq, both A and X are zero at the
- * branch target, otherwise they are zero at the next
- * insn.
- */
- if (BC == BC_EQ) {
- E->RI->Out2.RegA = E->RI->Out2.RegX = 0;
- } else {
- E->RI->Out.RegA = E->RI->Out.RegX = 0;
- }
- break;
-
- case OP65_TAY:
- case OP65_TYA:
- /* If the branch is a beq, both A and Y are zero at the
- * branch target, otherwise they are zero at the next
- * insn.
- */
- if (BC == BC_EQ) {
- E->RI->Out2.RegA = E->RI->Out2.RegY = 0;
- } else {
- E->RI->Out.RegA = E->RI->Out.RegY = 0;
- }
- break;
+ /* If this insn is a branch on zero flag, we may have more info on
+ * register contents for one of both flow directions, but only if
+ * there is a previous instruction.
+ */
+ if ((E->Info & OF_ZBRA) != 0 && (P = CS_GetPrevEntry (S, I)) != 0) {
+
+ /* Get the branch condition */
+ bc_t BC = GetBranchCond (E->OPC);
+
+ /* Check the previous instruction */
+ switch (P->OPC) {
+
+ case OP65_ADC:
+ case OP65_AND:
+ case OP65_DEA:
+ case OP65_EOR:
+ case OP65_INA:
+ case OP65_LDA:
+ case OP65_ORA:
+ case OP65_PLA:
+ case OP65_SBC:
+ /* A is zero in one execution flow direction */
+ if (BC == BC_EQ) {
+ E->RI->Out2.RegA = 0;
+ } else {
+ E->RI->Out.RegA = 0;
+ }
+ break;
+
+ case OP65_CMP:
+ /* If this is an immidiate compare, the A register has
+ * the value of the compare later.
+ */
+ if (CE_IsConstImm (P)) {
+ if (BC == BC_EQ) {
+ E->RI->Out2.RegA = (unsigned char)P->Num;
+ } else {
+ E->RI->Out.RegA = (unsigned char)P->Num;
+ }
+ }
+ break;
+
+ case OP65_CPX:
+ /* If this is an immidiate compare, the X register has
+ * the value of the compare later.
+ */
+ if (CE_IsConstImm (P)) {
+ if (BC == BC_EQ) {
+ E->RI->Out2.RegX = (unsigned char)P->Num;
+ } else {
+ E->RI->Out.RegX = (unsigned char)P->Num;
+ }
+ }
+ break;
+
+ case OP65_CPY:
+ /* If this is an immidiate compare, the Y register has
+ * the value of the compare later.
+ */
+ if (CE_IsConstImm (P)) {
+ if (BC == BC_EQ) {
+ E->RI->Out2.RegY = (unsigned char)P->Num;
+ } else {
+ E->RI->Out.RegY = (unsigned char)P->Num;
+ }
+ }
+ break;
+
+ case OP65_DEX:
+ case OP65_INX:
+ case OP65_LDX:
+ case OP65_PLX:
+ /* X is zero in one execution flow direction */
+ if (BC == BC_EQ) {
+ E->RI->Out2.RegX = 0;
+ } else {
+ E->RI->Out.RegX = 0;
+ }
+ break;
+
+ case OP65_DEY:
+ case OP65_INY:
+ case OP65_LDY:
+ case OP65_PLY:
+ /* X is zero in one execution flow direction */
+ if (BC == BC_EQ) {
+ E->RI->Out2.RegY = 0;
+ } else {
+ E->RI->Out.RegY = 0;
+ }
+ break;
+
+ case OP65_TAX:
+ case OP65_TXA:
+ /* If the branch is a beq, both A and X are zero at the
+ * branch target, otherwise they are zero at the next
+ * insn.
+ */
+ if (BC == BC_EQ) {
+ E->RI->Out2.RegA = E->RI->Out2.RegX = 0;
+ } else {
+ E->RI->Out.RegA = E->RI->Out.RegX = 0;
+ }
+ break;
+
+ case OP65_TAY:
+ case OP65_TYA:
+ /* If the branch is a beq, both A and Y are zero at the
+ * branch target, otherwise they are zero at the next
+ * insn.
+ */
+ if (BC == BC_EQ) {
+ E->RI->Out2.RegA = E->RI->Out2.RegY = 0;
+ } else {
+ E->RI->Out.RegA = E->RI->Out.RegY = 0;
+ }
+ break;
- default:
- break;
+ default:
+ break;
+ }
}
}
- }
+ } while (!Done);
+
}
projects / cc65 / blobdiff