/*
?*?File:????????alloc.c
?*?Purpose:?????generic?malloc（）?and?free（）?engine
?*
?*?Notes:???????99%?of?this?code?stolen/borrowed?from?the?K&R?C
?*??????????????examples.
?*
?*/

#include?“common.h“
#include?“stdlib.h“

#pragma?section?=?“HEAP“

/********************************************************************/

/*
?*?This?struct?forms?the?minimum?block?size?which?is?allocated?and
?*?also?forms?the?linked?list?for?the?memory?space?used?with?alloc（）
?*?and?free（）.??It?is?padded?so?that?on?a?32-bit?machine?all?malloc‘ed
?*?pointers?are?16-byte?aligned.
?*/
typedef?struct?ALLOC_HDR
{
????struct
????{
????????struct?ALLOC_HDR?????*ptr;
????????unsigned?int?size;
????}?s;
????unsigned?int?align;
????unsigned?int?pad;
}?ALLOC_HDR;

static?ALLOC_HDR?base;
static?ALLOC_HDR?*freep?=?NULL;

/********************************************************************/
void
free?（void?*ap）
{
????ALLOC_HDR?*bp?*p;

????bp?=?（ALLOC_HDR?*）ap?-?1;???/*?point?to?block?header?*/
????for?（p?=?freep;?!（（bp?>?p）?&&?（bp?s.ptr））?;?p?=?p->s.ptr）
????{
????????if?（（p?>=?p->s.ptr）?&&?（（bp?>?p）?||?（bp?s.ptr）））
????????{
????????????break;?/*?freed?block?at?start?or?end?of?arena?*/
????????}
????}

????if?（（bp?+?bp->s.size）?==?p->s.ptr）
????{
????????bp->s.size?+=?p->s.ptr->s.size;
????????bp->s.ptr?=?p->s.ptr->s.ptr;
????}
????else
????{
????????bp->s.ptr?=?p->s.ptr;
????}

????if?（（p?+?p->s.size）?==?bp）
????{
????????p->s.size?+=?bp->s.size;
????????p->s.ptr?=?bp->s.ptr;
????}
????else
????{
????????p->s.ptr?=?bp;
????}

????freep?=?p;
}

/********************************************************************/
void?*
malloc?（unsigned?nbytes）
{
????/*?Get?addresses?for?the?HEAP?start?and?end?*/
#if?（defined（CW））
????extern?char?__HEAP_START;
????extern?char?__HEAP_END[];
#elif?（defined（IAR））
????char?*__HEAP_START?=?__section_begin（“HEAP“）;
????char?*__HEAP_END?=?__section_end（“HEAP“）;
#endif

????ALLOC_HDR?*p?*prevp;
????unsigned?nunits;

????nunits?=?（（nbytes?+?sizeof（ALLOC_HDR）?-?1）?/?sizeof（ALLOC_HDR））?+?1;

????if?（（prevp?=?freep）?==?NULL）
????{
????????p?=?（ALLOC_HDR?*）__HEAP_START;
????????p->s.size?=?（?（（uint32）__HEAP_END?-?（uint32）__HEAP_START）
??????????????????????/?sizeof（ALLOC_HDR）?）;
????????p->s.ptr?=?&base;
????????base.s.ptr?=?p;
????????base.s.size?=?0;
????????prevp?=?freep?=?&base;
????}

????for?（p?=?prevp->s.ptr;?;?prevp?=?p?p?=?p->s.ptr）
????{
????????if?（p->s.size?>=?nunits）
????????{
????????????if?（p->s.size?==?nunits）
????????????{
????????????????prevp->s.ptr?=?p->s.ptr;
????????????}
????????????else
????????????{
????????????????p->s.size?-=?nunits;
????????????????p?+=?p->s.size;
????????????????p->s.size?=?nunits;
????????????}
????????????freep?=?prevp;
????????????return?（void?*）（p?+?1）;
????????}

????????if?（p?==?freep）
????????????return?NULL;
????}
}

/**************************************************

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2014-04-01?20:51??決賽程序\
?????文件?????????171??2014-02-22?11:45??決賽程序\TEST1.eww
?????目錄???????????0??2014-04-01?20:51??決賽程序\build\
?????目錄???????????0??2014-11-05?20:15??決賽程序\build\TEST1\
?????目錄???????????0??2014-04-01?20:51??決賽程序\build\TEST1\Debug\
?????目錄???????????0??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Exe\
?????文件???????60551??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Exe\fire_gpio_demo.hex
?????文件??????305708??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Exe\fire_gpio_demo.out
?????文件???????21559??2014-07-28?15:38??決賽程序\build\TEST1\Debug\Exe\fire_gpio_demo.sim
?????目錄???????????0??2014-07-28?15:34??決賽程序\build\TEST1\Debug\List\
?????文件???????36111??2014-07-28?15:34??決賽程序\build\TEST1\Debug\List\fire_gpio_demo.map
?????目錄???????????0??2014-11-05?20:15??決賽程序\build\TEST1\Debug\Obj\
?????文件???????21864??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\FTM.o
?????文件???????43508??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\LCDinit.o
?????文件???????14348??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\LED.o
?????文件????????9812??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\PIT.o
?????文件????????2361??2014-08-17?13:34??決賽程序\build\TEST1\Debug\Obj\TEST1.pbd
?????文件???????26584??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\adc.o
?????文件???????11840??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\alloc.o
?????文件???????17044??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\arm_cm4.o
?????文件????????8656??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\assert.o
?????文件???????54868??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\chu_li.o
?????文件????????1760??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\crt0.o
?????文件???????27876??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\data.o
?????文件????????9312??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\delay.o
?????文件???????22188??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\dma.o
?????文件????????8552??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\exti.o
?????文件???????18180??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\gpio.o
?????文件???????10440??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\io.o
?????文件???????19212??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\isr.o
?????文件????????9704??2014-07-28?15:34??決賽程序\build\TEST1\Debug\Obj\key.o
............此處省略249個文件信息