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- The cc65 assembler variable 'ptr1' (a general zero page pointer) is actually part of the cc65 zero page area so it's a bad idea (tm) to use it in swapping that very area.

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- The cc65 assembler variable 'sp' (the pointer to the C stack) is actually part of the cc65 zero page area so there's no need to manage it explicitly. Furthermore it is known to reside at the very start of the area so it can be initialized there for new threads.
This commit is contained in:
oliverschmidt 2007-08-10 10:45:35 +00:00
parent f8bf3e1428
commit 1c77f6f1d5
3 changed files with 120 additions and 90 deletions
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23
cpu/6502/mtarch.c
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@ -30,7 +30,7 @@
*
* Author: Adam Dunkels <adam@sics.se>
*
* $Id: mtarch.c,v 1.1 2007/04/21 22:15:45 oliverschmidt Exp $
* $Id: mtarch.c,v 1.2 2007/08/10 10:45:35 oliverschmidt Exp $
*/
#include <string.h>
@ -38,7 +38,6 @@
#include "mtarch.h"
unsigned char mtarch_asm_threadspreg;
unsigned char *mtarch_asm_threadsp;
unsigned char *mtarch_asm_threadzp;
unsigned char *mtarch_asm_threadstack;
@ -65,6 +64,10 @@ mtarch_start(struct mtarch_thread *thread,
memset(thread->cpustack, 0, sizeof(thread->cpustack));
memset(thread->cstack, 0, sizeof(thread->cstack));
/* Copy current zero page content as template. */
mtarch_asm_threadzp = &(thread->zp);
mtarch_asm_start();
/* Create a CPU stack frame with the appropriate values. */
thread->cpustack[MTARCH_CPUSTACKSIZE - 2] = ((unsigned short)function) / 0x100; /* high byte of return address */
thread->cpustack[MTARCH_CPUSTACKSIZE - 3] = ((unsigned short)function) % 0x100; /* low byte of return address */
@ -75,12 +78,12 @@ mtarch_start(struct mtarch_thread *thread,
thread->spreg = MTARCH_CPUSTACKSIZE - 8;
/* Setup the C stack with the data pointer. */
thread->cstack[MTARCH_CPUSTACKSIZE - 2] = ((unsigned short)data) / 0x100; /* high byte of data pointer */
thread->cstack[MTARCH_CPUSTACKSIZE - 3] = ((unsigned short)data) % 0x100; /* low byte of data pointer */
thread->sp = &thread->cstack[MTARCH_CSTACKSIZE - 3];
thread->cstack[MTARCH_CSTACKSIZE - 2] = ((unsigned short)data) / 0x100; /* high byte of data pointer */
thread->cstack[MTARCH_CSTACKSIZE - 3] = ((unsigned short)data) % 0x100; /* low byte of data pointer */
mtarch_asm_threadzp = &(thread->zp);
mtarch_asm_start();
/* Setup the C stack pointer. */
thread->zp[1] = ((size_t)&thread->cstack[MTARCH_CSTACKSIZE - 3]) / 0x100; /* high byte of C stack pointer */
thread->zp[0] = ((size_t)&thread->cstack[MTARCH_CSTACKSIZE - 3]) % 0x100; /* low byte of C stack pointer */
}
/*--------------------------------------------------------------------------*/
void
@ -95,14 +98,12 @@ mtarch_exec(struct mtarch_thread *thread)
/* Switch processor stack. The call to mtarch_asm_switch() will not
return until the process that we switch to calls yield(). */
mtarch_asm_threadspreg = thread->spreg;
mtarch_asm_threadsp = thread->sp;
mtarch_asm_threadstack = &(thread->cpustack[0]);
mtarch_asm_threadzp = &(thread->zp[0]);
mtarch_asm_threadstack = thread->cpustack;
mtarch_asm_threadzp = thread->zp;
mtarch_asm_exec();
thread->sp = mtarch_asm_threadsp;
thread->spreg = mtarch_asm_threadspreg;
}
/*--------------------------------------------------------------------------*/