[331] | 1 | /* va_list.c - tinycc support for va_list on X86_64 */
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| 2 |
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| 3 | #if defined __x86_64__
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| 4 |
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| 5 | /* Avoid include files, they may not be available when cross compiling */
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| 6 | extern void *memset(void *s, int c, __SIZE_TYPE__ n);
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| 7 | extern void abort(void);
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| 8 |
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| 9 | /* This should be in sync with our include/stdarg.h */
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| 10 | enum __va_arg_type {
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| 11 | __va_gen_reg, __va_float_reg, __va_stack
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| 12 | };
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| 13 |
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| 14 | /* GCC compatible definition of va_list. */
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| 15 | typedef struct {
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| 16 | unsigned int gp_offset;
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| 17 | unsigned int fp_offset;
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| 18 | union {
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| 19 | unsigned int overflow_offset;
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| 20 | char *overflow_arg_area;
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| 21 | };
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| 22 | char *reg_save_area;
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| 23 | } __va_list_struct;
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| 24 |
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| 25 | void __va_start(__va_list_struct *ap, void *fp)
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| 26 | {
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| 27 | memset(ap, 0, sizeof(__va_list_struct));
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| 28 | *ap = *(__va_list_struct *)((char *)fp - 16);
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| 29 | ap->overflow_arg_area = (char *)fp + ap->overflow_offset;
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| 30 | ap->reg_save_area = (char *)fp - 176 - 16;
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| 31 | }
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| 32 |
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| 33 | void *__va_arg(__va_list_struct *ap,
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| 34 | enum __va_arg_type arg_type,
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| 35 | int size, int align)
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| 36 | {
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| 37 | size = (size + 7) & ~7;
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| 38 | align = (align + 7) & ~7;
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| 39 | switch (arg_type) {
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| 40 | case __va_gen_reg:
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| 41 | if (ap->gp_offset + size <= 48) {
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| 42 | ap->gp_offset += size;
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| 43 | return ap->reg_save_area + ap->gp_offset - size;
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| 44 | }
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| 45 | goto use_overflow_area;
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| 46 |
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| 47 | case __va_float_reg:
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| 48 | if (ap->fp_offset < 128 + 48) {
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| 49 | ap->fp_offset += 16;
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| 50 | return ap->reg_save_area + ap->fp_offset - 16;
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| 51 | }
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| 52 | size = 8;
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| 53 | goto use_overflow_area;
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| 54 |
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| 55 | case __va_stack:
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| 56 | use_overflow_area:
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| 57 | ap->overflow_arg_area += size;
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| 58 | ap->overflow_arg_area = (char*)((long long)(ap->overflow_arg_area + align - 1) & -align);
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| 59 | return ap->overflow_arg_area - size;
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| 60 |
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| 61 | default: /* should never happen */
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| 62 | abort();
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| 63 | }
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| 64 | }
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| 65 | #endif
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