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comparison src/cpu.c @ 2:6204c81e2933

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Revert changes to handling of immediate versions of bitwise instructions. Replace asri with cmpi.
author Michael Pavone <pavone@retrodev.com>
date Wed, 23 Mar 2016 19:19:29 -0700
parents 7e44f7d5810b
children 74a6d629b78f
comparison
equal deleted inserted replaced
1:a44e078d792b 2:6204c81e2933
214 context->regs[REG_PC] += sign_extend(a << 4 | b) * 2; 214 context->regs[REG_PC] += sign_extend(a << 4 | b) * 2;
215 context->state = STATE_NEED_FETCH; 215 context->state = STATE_NEED_FETCH;
216 } 216 }
217 } 217 }
218 218
219 uint16_t format_immediate_bitwise(uint16_t val) 219 uint16_t format_immediate(uint16_t val)
220 { 220 {
221 if (val & 8) { 221 if (val & 8) {
222 val |= 0xFFF0; 222 val |= 0xFFF0;
223 } 223 }
224 return val;
225 }
226
227 uint16_t format_immediate(uint16_t val)
228 {
229 val = format_immediate_bitwise(val);
230 if (!val) { 224 if (!val) {
231 val = 8; 225 val = 8;
232 } 226 }
233 return val; 227 return val;
234 } 228 }
337 tmp = context->regs[dst] + format_immediate(a); 331 tmp = context->regs[dst] + format_immediate(a);
338 context->regs[dst] = tmp; 332 context->regs[dst] = tmp;
339 update_flags_arith(context, tmp); 333 update_flags_arith(context, tmp);
340 break; 334 break;
341 case ANDI: 335 case ANDI:
342 context->regs[dst] = context->regs[dst] & format_immediate_bitwise(a); 336 context->regs[dst] = context->regs[dst] & format_immediate(a);
343 update_flags_bitwise(context, context->regs[dst]); 337 update_flags_bitwise(context, context->regs[dst]);
344 break; 338 break;
345 case ORI: 339 case ORI:
346 context->regs[dst] = context->regs[dst] | format_immediate_bitwise(a); 340 context->regs[dst] = context->regs[dst] | format_immediate(a);
347 update_flags_bitwise(context, context->regs[dst]); 341 update_flags_bitwise(context, context->regs[dst]);
348 break; 342 break;
349 case LSI: 343 case LSI:
350 shift = a & 7; 344 shift = a & 7;
351 if (!shift) { 345 if (!shift) {
358 tmp = context->regs[dst] << (a & 7); 352 tmp = context->regs[dst] << (a & 7);
359 } 353 }
360 context->regs[dst] = tmp; 354 context->regs[dst] = tmp;
361 update_flags_arith(context, tmp); 355 update_flags_arith(context, tmp);
362 break; 356 break;
363 case ASRI: 357 case CMPI:
364 shift = a; 358 tmp = a;
365 if (!shift) { 359 if (a & 8) {
366 shift = 16; 360 a |= 0xFFF0;
367 } 361 }
368 tmp = context->regs[dst]; 362 tmp = context->regs[dst] - a;
369 if (tmp & 0x8000) {
370 tmp |= 0xFFFF0000;
371 }
372 tmp = tmp >> shift & 0xFFFF;
373 tmp |= (context->regs[dst] >> (context->regs[shift] - 1)) << 16 & 0x10000;
374 context->regs[dst] = tmp;
375 update_flags_arith(context, tmp); 363 update_flags_arith(context, tmp);
376 break; 364 break;
377 case SINGLE_REG: 365 case SINGLE_REG:
378 run_single_reg(context, dst, a); 366 run_single_reg(context, dst, a);
379 return; 367 return;