mach_dep.c

内存垃圾收集程序

# include "runtime.h"

/* Call allocobj or allocaobj after first saving at least those registers */
/* not preserved by the C compiler. The register used for return values   */
/* is not saved, since it will be clobbered anyway.                       */
# ifdef RT
    /* This is done in rt_allocobj.s */
# else
asm("    .text");
asm("	.globl  __allocobj");
asm("	.globl  __allocaobj");
asm("	.globl  _allocobj");
asm("	.globl  _allocaobj");

# ifdef M68K
    asm("_allocobj:");
    asm("   link    a6,#0");
    asm("	movl    d1,sp@-");
    asm("	movl    a0,sp@-");
    asm("	movl    a1,sp@-");
    asm("	movl    sp@(20),sp@-");
    asm("	jbsr    __allocobj");
    asm("	addl    #4,sp");
    asm("	movl    sp@+,a1");
    asm("	movl    sp@+,a0");
    asm("	movl    sp@+,d1");
    asm("	unlk    a6");
    asm("	rts");
    
    asm("_allocaobj:");
    asm("	link    a6,#0");
    asm("	movl    d1,sp@-");
    asm("	movl    a0,sp@-");
    asm("	movl    a1,sp@-");
    asm("	movl    sp@(20),sp@-");
    asm("	jbsr    __allocaobj");
    asm("	addl    #4,sp");
    asm("	movl    sp@+,a1");
    asm("	movl    sp@+,a0");
    asm("	movl    sp@+,d1");
    asm("	unlk    a6");
    asm("	rts");
# endif

# ifdef I386
    asm(".data");
    asm("gc_ret_value: .word 0");
    asm(".word 0");
    asm(".text");

    asm("_allocaobj:");
    asm("pushl %ebp");
    asm("movl %esp,%ebp");
    asm("pushal");
    asm("pushl 8(%ebp)");          /* Push orignal argument */
    asm("call __allocaobj");
    asm("popl %ecx");
    asm("movl %eax,gc_ret_value");  /* Save return value */
    asm("popal");
    asm("movl gc_ret_value,%eax");
    asm("leave");
    asm("ret");

    asm("_allocobj:");
    asm("pushl %ebp");
    asm("movl %esp,%ebp");
    asm("pushal");
    asm("pushl 8(%ebp)");          /* Push orignal argument */
    asm("call __allocobj");
    asm("popl %ecx");
    asm("movl %eax,gc_ret_value");  /* Save return value */
    asm("popal");
    asm("movl gc_ret_value,%eax");
    asm("leave");
    asm("ret");
# endif

# ifdef SPARC
    asm("_allocaobj:");
    asm("	ba	__allocaobj");
    asm("	nop");
    asm("_allocobj:");
    asm("	ba	__allocobj");
    asm("	nop");
    
#   include <sun4/trap.h>
    asm("	.globl	_save_regs_in_stack");
    asm("_save_regs_in_stack:");
    asm("	t	0x3   ! ST_FLUSH_WINDOWS");
    asm("	mov	%sp,%o0");
    asm("	retl");
    asm("	nop");
# endif

# ifdef VAX
    asm("_allocobj:");
    asm(".word    0x3e");
    asm("pushl   4(ap)");
    asm("calls   $1,__allocobj");
    asm("ret");
    asm("_allocaobj:");
    asm(".word   0x3e");
    asm("pushl   4(ap)");
    asm("calls   $1,__allocaobj");
    asm("ret");
# endif

# ifdef NS32K
    asm("_allocobj:");
    asm("enter [],$0");
    asm("movd r1,tos");
    asm("movd r2,tos");
    asm("movd 8(fp),tos");
    asm("bsr ?__allocobj");
    asm("adjspb $-4");
    asm("movd tos,r2");
    asm("movd tos,r1");
    asm("exit []");
    asm("ret $0");
    asm("_allocaobj:");
    asm("enter [],$0");
    asm("movd r1,tos");
    asm("movd r2,tos");
    asm("movd 8(fp),tos");
    asm("bsr ?__allocaobj");
    asm("adjspb $-4");
    asm("movd tos,r2");
    asm("movd tos,r1");
    asm("exit []");
    asm("ret $0");
# endif


# if !defined(VAX) && !defined(M68K) && !defined(SPARC) && !defined(I386) && !defined(NS32K)
    --> fix it
# endif

# endif

/* Routine to mark from registers that are preserved by the C compiler */
mark_regs()
{
#       ifdef RT
	  register long TMP_SP; /* must be bound to r11 */
#       endif
#       ifdef VAX
	  /* r1 through r5 are preserved by allocobj, and therefore     */
	  /* on the stack.                                              */
	  asm("pushl r11");     asm("calls $1,_tl_mark");
	  asm("pushl r10"); 	asm("calls $1,_tl_mark");
	  asm("pushl r9");	asm("calls $1,_tl_mark");
	  asm("pushl r8");	asm("calls $1,_tl_mark");
	  asm("pushl r7");	asm("calls $1,_tl_mark");
	  asm("pushl r6");	asm("calls $1,_tl_mark");

	  asm("movl sp,r11");		/* TMP_SP = stack pointer sp	*/
#       endif
#       ifdef M68K
	  /* a0, a1 and d1 are preserved by allocobj */
	  /*  and therefore are on stack             */
	
	  asm("subqw #0x4,sp");		/* allocate word on top of stack */

	  asm("movl a0,sp@");	asm("jbsr _tl_mark");
	  asm("movl a1,sp@");	asm("jbsr _tl_mark");
	  asm("movl a2,sp@");	asm("jbsr _tl_mark");
	  asm("movl a3,sp@");	asm("jbsr _tl_mark");
	  asm("movl a4,sp@");	asm("jbsr _tl_mark");
	  asm("movl a5,sp@");	asm("jbsr _tl_mark");
	  /* Skip frame pointer and stack pointer */
	  asm("movl d0,sp@");	asm("jbsr _tl_mark");
	  asm("movl d1,sp@");	asm("jbsr _tl_mark");
	  asm("movl d2,sp@");	asm("jbsr _tl_mark");
	  asm("movl d3,sp@");	asm("jbsr _tl_mark");
	  asm("movl d4,sp@");	asm("jbsr _tl_mark");
	  asm("movl d5,sp@");	asm("jbsr _tl_mark");
	  asm("movl d6,sp@");	asm("jbsr _tl_mark");
	  asm("movl d7,sp@");	asm("jbsr _tl_mark");

	  asm("addqw #0x4,sp");		/* put stack back where it was	*/

	  asm("movl a7,d7");		/* TMP_SP = stack pointer a7	*/
#       endif

#       ifdef I386
	  asm("pushl %eax");  asm("call _tl_mark"); asm("addl $4,%esp");
	  asm("pushl %ecx");  asm("call _tl_mark"); asm("addl $4,%esp");
	  asm("pushl %edx");  asm("call _tl_mark"); asm("addl $4,%esp");
	  asm("pushl %esi");  asm("call _tl_mark"); asm("addl $4,%esp");
	  asm("pushl %edi");  asm("call _tl_mark"); asm("addl $4,%esp");
	  asm("pushl %ebx");  asm("call _tl_mark"); asm("addl $4,%esp");
#       endif

#       ifdef NS32K
	  asm ("movd r3, tos"); asm ("bsr ?_tl_mark"); asm ("adjspb $-4");
	  asm ("movd r4, tos"); asm ("bsr ?_tl_mark"); asm ("adjspb $-4");
	  asm ("movd r5, tos"); asm ("bsr ?_tl_mark"); asm ("adjspb $-4");
	  asm ("movd r6, tos"); asm ("bsr ?_tl_mark"); asm ("adjspb $-4");
	  asm ("movd r7, tos"); asm ("bsr ?_tl_mark"); asm ("adjspb $-4");
#       endif

#       ifdef SPARC
	  save_regs_in_stack();
#       endif

#	ifdef RT
	  /* we used to think this wasn't necessary, but gcollect */
	  /* can be called from many places ...                   */
	    tl_mark(TMP_SP);	/* tl_mark from r11 */

	    asm("cas r11, r6, r0"); tl_mark(TMP_SP);	/* r6 */
	    asm("cas r11, r7, r0"); tl_mark(TMP_SP);	/* through */
	    asm("cas r11, r8, r0"); tl_mark(TMP_SP);	/* r10 */
	    asm("cas r11, r9, r0"); tl_mark(TMP_SP);
	    asm("cas r11, r10, r0"); tl_mark(TMP_SP);

	    asm("cas r11, r12, r0"); tl_mark(TMP_SP); /* r12 */
	    asm("cas r11, r13, r0"); tl_mark(TMP_SP); /* through */
	    asm("cas r11, r14, r0"); tl_mark(TMP_SP); /* r15 */
	    asm("cas r11, r15, r0"); tl_mark(TMP_SP);
#	endif

      /* other machines... */
#       if !(defined M68K) && !(defined VAX) && !(defined RT) && !(defined SPARC) && !(defined I386) &&!(defined NS32K)
	    --> bad news <--
#       endif
}