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Optimized the condes routine, because it is used to schedule interrupt

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handlers on many platforms, so too many cycles are evil.


git-svn-id: svn://svn.cc65.org/cc65/trunk@2962 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz 2004-03-25 07:58:58 +00:00
parent ac08caec07
commit e4554505d6
1 changed files with 36 additions and 51 deletions
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87
libsrc/runtime/condes.s
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@ -4,9 +4,9 @@
; CC65 runtime: Support for calling module constructors/destructors
;
; The condes routine must be called with the table address in a/x and the
; size of the table in y. The current implementation limits the table size
; to 254 bytes (127 vectors) but this shouldn't be problem for now and may
; be changed later.
; size of the table (which must not be zero!) in y. The current implementation
; limits the table size to 254 bytes (127 vectors) but this shouldn't be
; problem for now and may be changed later.
;
; libinit and libdone call condes with the predefined module constructor and
; destructor tables, they must be called from the platform specific startup
@ -27,11 +27,12 @@
.proc initlib
ldy #<(__CONSTRUCTOR_COUNT__*2)
beq exit
lda #<__CONSTRUCTOR_TABLE__
ldx #>__CONSTRUCTOR_TABLE__
ldy #<(__CONSTRUCTOR_COUNT__*2)
bne condes
rts
jmp condes
exit: rts
.endproc
@ -41,57 +42,41 @@
.proc donelib
lda #<__DESTRUCTOR_TABLE__
ldx #>__DESTRUCTOR_TABLE__
ldy #<(__DESTRUCTOR_COUNT__*2)
bne condes
rts
ldy #<(__DESTRUCTOR_COUNT__*2)
beq initlib::exit
lda #<__DESTRUCTOR_TABLE__
ldx #>__DESTRUCTOR_TABLE__
jmp condes
.endproc
; --------------------------------------------------------------------------
; Generic table call handler. We cannot use callax here, since condes is also
; used for interrupt handlers, and callax clobbers ptr1.
.proc condes
sta getbyt+1
stx getbyt+2
sty index
loop: ldy index
beq done
dey
jsr getbyt
sta jmpvec+2
dey
jsr getbyt
sta jmpvec+1
sty index
jsr jmpvec
.if (.cpu .bitand ::CPU_ISET_65SC02)
bra loop
.else
jmp loop
.endif
done: rts
.endproc
; --------------------------------------------------------------------------
; Data. The getbyte and jmpvec routines are placed in the data segment
; cause they're patched at runtime.
.bss
index: .byte 0
; Generic table call handler. Since the routine is also used to call a table
; of interrupt handlers, it uses heavily self modifying code for performance
; reasons. It will go into the data segment for this reason ...
; NOTE: The routine must not be called if the table is empty!
.data
getbyt: lda $FFFF,y
rts
.proc condes
sta fetch1+1
stx fetch1+2
sta fetch2+1
stx fetch2+2
loop: dey
fetch1: lda $FFFF,y ; Patched at runtime
sta jmpvec+2
dey
fetch2: lda $FFFF,y ; Patched at runtime
sta jmpvec+1
sty index+1
jmpvec: jsr $FFFF ; Patched at runtime
index: ldy #$FF ; Patched at runtime
bne loop
rts
.endproc
jmpvec: jmp $0000