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Added g_branch() to cc65's code generator.

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It uses BRA if the platform's CPU has BRA.  Else, it generates a JMP.

(Used it in the bitfield sign-extending code.)
This commit is contained in:
Greg King 2020-08-18 19:07:29 -04:00
parent 0690a12ad2
commit 36dd82f0e6
2 changed files with 31 additions and 10 deletions
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34
src/cc65/codegen.c
View File

@ -2207,7 +2207,7 @@ void g_restore (unsigned flags)
void g_cmp (unsigned flags, unsigned long val)
/* Immidiate compare. The primary register will not be changed, Z flag
/* Immediate compare. The primary register will not be changed, Z flag
** will be set.
*/
{
@ -2455,6 +2455,21 @@ void g_falsejump (unsigned flags attribute ((unused)), unsigned label)
}
void g_branch (unsigned Label)
/* Branch unconditionally to Label if the CPU has the BRA instruction.
** Otherwise, jump to Label.
*/
{
if ((CPUIsets[CPU] & CPU_ISET_65SC02) != 0) {
AddCodeLine ("bra %s", LocalLabelName (Label));
} else {
g_jump (Label);
}
}
void g_lateadjustSP (unsigned label)
/* Adjust stack based on non-immediate data */
{
@ -2761,12 +2776,14 @@ void g_div (unsigned flags, unsigned long val)
AddCodeLine ("lsr a");
g_restore (flags);
AddCodeLine ("bcs %s", LocalLabelName (DoShiftLabel));
/* The result is 0. We can just load 0 and skip the shifting. */
g_getimmed (flags | CF_ABSOLUTE, 0, 0);
/* TODO: replace with BEQ? Would it be optimized? */
g_jump (EndLabel);
/* Do the shift. The sign of the result may need be corrected
/* Do the shift. The sign of the result may need to be corrected
** later.
*/
g_defcodelabel (DoShiftLabel);
@ -4511,18 +4528,17 @@ void g_extractbitfield (unsigned Flags, unsigned FullWidthFlags, int IsSigned,
unsigned ZeroExtendLabel = GetLocalLabel ();
AddCodeLine ("beq %s", LocalLabelName (ZeroExtendLabel));
/* Pop A back and sign extend if required; operating on the full result need
/* Pop A back and sign-extend if required; operating on the full result needs
** to sign-extend into high byte, too.
*/
AddCodeLine ("pla");
g_or (FullWidthFlags | CF_CONST, ~Mask);
/* Apparently, there is no unconditional branch BRA, so use JMP. */
unsigned DoneLabel = GetLocalLabel ();
AddCodeLine ("jmp %s", LocalLabelName (DoneLabel));
g_branch (DoneLabel);
/* Pop A back, then zero-extend; we need to duplicate the PLA rather than move it before
** the branch to share with the other label because PLA sets the condition codes.
/* Pop A back, then zero-extend. We need to duplicate the PLA, rather than move it before
** the branch to share with the other label, because PLA changes some condition codes.
*/
g_defcodelabel (ZeroExtendLabel);
AddCodeLine ("pla");
@ -4534,7 +4550,7 @@ void g_extractbitfield (unsigned Flags, unsigned FullWidthFlags, int IsSigned,
g_defcodelabel (DoneLabel);
} else {
/* Unsigned bit-field, only needs zero-extension. */
/* Unsigned bit-field, needs only zero-extension. */
if (ZeroExtendMask != 0) {
g_and (FullWidthFlags | CF_CONST, ZeroExtendMask);
}

7
src/cc65/codegen.h
View File

@ -380,7 +380,7 @@ void g_restore (unsigned flags);
/* Copy hold register to primary. */
void g_cmp (unsigned flags, unsigned long val);
/* Immidiate compare. The primary register will not be changed, Z flag
/* Immediate compare. The primary register will not be changed, Z flag
** will be set.
*/
@ -410,6 +410,11 @@ void g_truejump (unsigned flags, unsigned label);
void g_falsejump (unsigned flags, unsigned label);
/* Jump to label if zero flag set */
void g_branch (unsigned Label);
/* Branch unconditionally to Label if the CPU has the BRA instruction.
** Otherwise, jump to Label.
*/
void g_lateadjustSP (unsigned label);
/* Adjust stack based on non-immediate data */