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1 /*
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2 * pragma.c
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3 *
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4 * stuff associated with lwasm specific strangeness
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5 */
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6
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7 #include <ctype.h>
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8 #include <stdlib.h>
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9 #include <string.h>
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10 #include "lwasm.h"
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11
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12 /*
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13 A pragma is a means of controlling code generation.
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14
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15 The pseudo op "*pragma" which will be treated as a comment by an assembler
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16 that doesn't recognize it and thus will not cause assembly errors. This is
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17 the preferred way of flagging a pragma if it will not cause incorrect
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18 execution of the program.
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19
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20 The pseudo op "pragma" which will cause an error on an assembler that does
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21 not understand it.
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22
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23 In the case of "*pragma", unrecognized pragmas MUST be silently ignored. In
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24 the case of "pragma", unrecognized pragmas should raise an error.
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25
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26 LWASM understands the following pragmas:
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27
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28 index0tonone
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29 noindex0tonone
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30
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31 When set (index0tonone), an expression that evaluates to 0, other than a
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32 bare constant, in a <offset>,r operand will cause the code for ",r" to be
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33 emitted rather than "0,r". If not set (noindex0tonone), the "0,r" output
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34 will be emitted. The default is to perform the optimization.
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35
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36 This particular optimization will save a cycle for a direct operation. For
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37 an indirect operation, however, it will save several cycles and a program byte
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38 which may be very useful.
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39 */
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40
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41 void pseudo_pragma_real(asmstate_t *as, sourceline_t *cl, char **optr, int error)
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42 {
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43 char pragma[128];
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44 int c = 0;
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45
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46 while (isspace(**optr))
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47 (*optr)++;
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48
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49 while (c < 127 && **optr && !isspace(**optr))
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50 {
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51 pragma[c++] = **optr;
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52 (*optr)++;
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53 }
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54
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55 if (c == 0 || (**optr && !isspace(**optr)))
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56 {
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57 if (error)
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58 errorp1(ERR_PRAGMA);
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59 return;
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60 }
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61 pragma[c] = 0;
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62 if (!strcmp(pragma, "noindex0tonone"))
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63 {
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64 as -> pragmas |= PRAGMA_NOINDEX0TONONE;
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65 }
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66 else if (!strcmp(pragma, "index0tonone"))
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67 {
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68 as -> pragmas &= ~PRAGMA_NOINDEX0TONONE;
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69 }
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70 else
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71 {
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72 if (error)
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73 errorp1(ERR_PRAGMA);
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74 }
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75 }
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76
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77 void pseudo_pragma(asmstate_t *as, sourceline_t *cl, char **optr)
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78 {
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79 pseudo_pragma_real(as, cl, optr, 1);
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80 }
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81
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82 void pseudo_starpragma(asmstate_t *as, sourceline_t *cl, char **optr)
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83 {
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84 pseudo_pragma_real(as, cl, optr, 0);
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85 }
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