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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