1985-06-10 15:32:18 +00:00
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#define RCSID5 "$Header$"
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/*
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* Motorola 6809 special routines
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*/
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branch(opc, exp)
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register int opc;
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expr_t exp;
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{
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register int sm, dist;
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int saving;
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dist = exp.val - (DOTVAL + 2);
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if (pass == PASS_2 && dist > 0 && !(exp.typ & S_DOT))
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dist -= DOTGAIN;
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sm = fitb(dist);
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if ((exp.typ & ~S_DOT) != DOTTYP)
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sm = 0;
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if (opc == 0x8D || opc == 0x20)
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saving = 1;
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else
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saving = 2;
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if ((sm = small(sm,saving)) == 0) {
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dist--;
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if (opc == 0x8D) /* bsr */
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opc = 0x17;
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else if (opc == 0x20) /* bra */
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opc = 0x16;
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else {
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emit1(0x10);
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dist--;
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}
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}
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emit1(opc);
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if (sm == 0) {
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#ifdef RELOCATION
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newrelo(exp.typ, RELPC|RELO2|RELBR);
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#endif
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emit2(dist);
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} else
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emit1(lowb(dist));
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}
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regno(r) register r; {
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switch (r) {
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case X: return 0;
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case Y: return 0x20;
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case U: return 0x40;
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case S: return 0x60;
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}
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return -1;
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}
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emit1or2(n) {
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if (n & ~0xFF)
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emit1(n >> 8);
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emit1(n);
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}
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offset(reg, exp, ind)
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register int reg, ind;
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expr_t exp;
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{
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if (reg == PC) {
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int sm, dist;
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dist = exp.val - (DOTVAL + 2);
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if (pass == PASS_2 && dist > 0 && !(exp.typ & S_DOT))
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dist -= DOTGAIN;
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sm = fitb(dist);
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if ((exp.typ & S_TYP) != DOTTYP)
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sm = 0;
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1986-12-05 16:36:40 +00:00
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if (small(sm,1)) {
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1985-06-10 15:32:18 +00:00
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emit1(0x8C + ind);
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emit1(dist);
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} else {
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emit1(0x8D + ind);
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1986-12-05 16:36:40 +00:00
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emit1((dist-1)>>8);
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1985-06-10 15:32:18 +00:00
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emit1(dist - 1);
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}
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} else if ((reg = regno(reg)) < 0)
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serror("register error");
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else if ((exp.typ & S_TYP) == S_ABS && exp.val == 0)
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emit1(0x84 + reg + ind); /* XOP 0, REG == XOP , REG */
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else if (ind == 0 && (exp.typ & S_TYP) == S_ABS &&
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-16 <= exp.val && exp.val <= 15
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)
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emit1(reg + ind + (exp.val & 037));
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else if ((exp.typ&S_TYP)==S_ABS && -256<=exp.val && exp.val<=255) {
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emit1(0x88 + reg + ind);
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emit1(exp.val);
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} else {
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emit1(0x89 + reg + ind);
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#ifdef RELOCATION
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newrelo(exp.typ, RELO2|RELBR);
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#endif
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emit2(exp.val);
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}
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}
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