From bb4f3c447547c496dc3861e0a114ef8abc9d64b5 Mon Sep 17 00:00:00 2001 From: cuz Date: Wed, 19 Jul 2000 09:23:51 +0000 Subject: [PATCH] Use macpack for debugging, cosmetic changes git-svn-id: svn://svn.cc65.org/cc65/trunk@171 b7a2c559-68d2-44c3-8de9-860c34a00d81 --- libsrc/common/free.s | 52 ++++++++++++++++++++++++-------------------- 1 file changed, 28 insertions(+), 24 deletions(-) diff --git a/libsrc/common/free.s b/libsrc/common/free.s index faa40c672..8caf04d4b 100644 --- a/libsrc/common/free.s +++ b/libsrc/common/free.s @@ -64,42 +64,46 @@ .import pushax, __hadd .export _free -; Offsets into struct freeblock + .macpack generic + +; Offsets into struct freeblock and other constant stuff + +size = 0 +next = 2 +prev = 4 +admin_space = 2 +min_size = 6 - size = 0 - next = 2 - prev = 4 ; Code _free: sta ptr1 - stx ptr1+1 ; Save block + stx ptr1+1 ; Save block ; Is the argument NULL? - ora ptr1+1 ; Is the argument NULL? - beq @L9 ; Jump if yes + ora ptr1+1 ; Is the argument NULL? + beq @L9 ; Jump if yes -; Decrement the given pointer by 2. The size of the block is stored there. +; Decrement the given pointer by the admin space amount, so it points to the +; real block allocated. The size of the block is stored in the admin space. ; Remember the block size in ptr2. - sec lda ptr1 - sbc #2 + sub #admin_space sta ptr1 bcs @L1 dec ptr1+1 @L1: ldy #size+1 - lda (ptr1),y ; High byte of size - sta ptr2+1 ; Save it + lda (ptr1),y ; High byte of size + sta ptr2+1 ; Save it dey lda (ptr1),y sta ptr2 ; Check if the block is on top of the heap - clc - adc ptr1 + add ptr1 tay lda ptr1+1 adc ptr2+1 @@ -126,12 +130,11 @@ _free: sta ptr1 lda __hlast+1 sta ptr2+1 ; Pointer to last block now in ptr2 - clc ldy #size lda (ptr2),y ; Low byte of block size - adc ptr2 + add ptr2 tax - iny ; High byte of block size + iny ; High byte of block size lda (ptr2),y adc ptr2+1 @@ -151,14 +154,14 @@ _free: sta ptr1 ldy #prev+1 ; Offset of ->prev field lda (ptr2),y - sta ptr1+1 ; Remember f->prev in ptr1 + sta ptr1+1 ; Remember f->prev in ptr1 sta __hlast+1 dey lda (ptr2),y - sta ptr1 ; Remember f->prev in ptr1 + sta ptr1 ; Remember f->prev in ptr1 sta __hlast - ora __hlast+1 ; -> prev == 0? - bne @L8 ; Jump if free list not empty + ora __hlast+1 ; -> prev == 0? + bne @L8 ; Jump if free list not empty ; Free list is now empty (A = 0) @@ -172,11 +175,11 @@ _free: sta ptr1 ; Block before is now last block. ptr1 points to f->prev. @L8: lda #$00 - dey ; Points to high byte of ->next + dey ; Points to high byte of ->next sta (ptr1),y - dey ; Low byte of f->prev->next + dey ; Low byte of f->prev->next sta (ptr1),y - rts ; Done + rts ; Done ; The block is not on top of the heap. Add it to the free list. @@ -191,3 +194,4 @@ _free: sta ptr1 + -- 2.39.5