Mercurial > repos > blastem
diff m68k_to_x86.c @ 207:c82f65a87a53
Fix overflow flag on ASL
author | Mike Pavone <pavone@retrodev.com> |
---|---|
date | Fri, 25 Jan 2013 18:39:22 -0800 |
parents | 7c227a8ec53d |
children | 3457dc6fd558 |
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--- a/m68k_to_x86.c Wed Jan 23 21:54:58 2013 -0800 +++ b/m68k_to_x86.c Fri Jan 25 18:39:22 2013 -0800 @@ -92,7 +92,7 @@ void print_regs_exit(m68k_context * context) { - printf("XNVZC\n%d%d%d%d%d\n", context->flags[0], context->flags[1], context->flags[2], context->flags[3], context->flags[4]); + printf("XNZVC\n%d%d%d%d%d\n", context->flags[0], context->flags[1], context->flags[2], context->flags[3], context->flags[4]); for (int i = 0; i < 8; i++) { printf("d%d: %X\n", i, context->dregs[i]); } @@ -2619,6 +2619,8 @@ uint8_t * translate_shift(uint8_t * dst, m68kinst * inst, x86_ea *src_op, x86_ea * dst_op, x86_68k_options * opts, shift_ir_t shift_ir, shift_irdisp8_t shift_irdisp8, shift_clr_t shift_clr, shift_clrdisp8_t shift_clrdisp8, shift_ir_t special, shift_irdisp8_t special_disp8) { uint8_t * end_off = NULL; + uint8_t * nz_off = NULL; + uint8_t * z_off = NULL; if (inst->src.addr_mode == MODE_UNUSED) { dst = cycles(dst, BUS); //Memory shift @@ -2626,10 +2628,24 @@ } else { dst = cycles(dst, inst->extra.size == OPSIZE_LONG ? 8 : 6); if (src_op->mode == MODE_IMMED) { - if (dst_op->mode == MODE_REG_DIRECT) { - dst = shift_ir(dst, src_op->disp, dst_op->base, inst->extra.size); + if (src_op->disp != 1 && inst->op == M68K_ASL) { + dst = mov_ir(dst, 0, FLAG_V, SZ_B); + for (int i = 0; i < src_op->disp; i++) { + if (dst_op->mode == MODE_REG_DIRECT) { + dst = shift_ir(dst, 1, dst_op->base, inst->extra.size); + } else { + dst = shift_irdisp8(dst, 1, dst_op->base, dst_op->disp, inst->extra.size); + } + //dst = setcc_r(dst, CC_O, FLAG_V); + dst = jcc(dst, CC_NO, dst+4); + dst = mov_ir(dst, 1, FLAG_V, SZ_B); + } } else { - dst = shift_irdisp8(dst, src_op->disp, dst_op->base, dst_op->disp, inst->extra.size); + if (dst_op->mode == MODE_REG_DIRECT) { + dst = shift_ir(dst, src_op->disp, dst_op->base, inst->extra.size); + } else { + dst = shift_irdisp8(dst, src_op->disp, dst_op->base, dst_op->disp, inst->extra.size); + } } } else { if (src_op->base != RCX) { @@ -2638,58 +2654,92 @@ } else { dst = mov_rdisp8r(dst, src_op->base, src_op->disp, RCX, SZ_B); } + } dst = and_ir(dst, 63, RCX, SZ_D); + nz_off = dst+1; + dst = jcc(dst, CC_NZ, dst+2); + //Flag behavior for shift count of 0 is different for x86 than 68K + if (dst_op->mode == MODE_REG_DIRECT) { + dst = cmp_ir(dst, 0, dst_op->base, inst->extra.size); + } else { + dst = cmp_irdisp8(dst, 0, dst_op->base, dst_op->disp, inst->extra.size); + } + dst = setcc_r(dst, CC_Z, FLAG_Z); + dst = setcc_r(dst, CC_S, FLAG_N); + dst = mov_ir(dst, 0, FLAG_C, SZ_B); + //For other instructions, this flag will be set below + if (inst->op == M68K_ASL) { + dst = mov_ir(dst, 0, FLAG_V, SZ_B); + } + z_off = dst+1; + dst = jmp(dst, dst+2); + *nz_off = dst - (nz_off + 1); //add 2 cycles for every bit shifted dst = add_rr(dst, RCX, CYCLES, SZ_D); dst = add_rr(dst, RCX, CYCLES, SZ_D); - //x86 shifts modulo 32 for operand sizes less than 64-bits - //but M68K shifts modulo 64, so we need to check for large shifts here - dst = cmp_ir(dst, 32, RCX, SZ_B); - uint8_t * norm_shift_off = dst + 1; - dst = jcc(dst, CC_L, dst+2); - if (special) { - if (inst->extra.size == OPSIZE_LONG) { - uint8_t * neq_32_off = dst + 1; - dst = jcc(dst, CC_NZ, dst+2); - - //set the carry bit to the lsb - if (dst_op->mode == MODE_REG_DIRECT) { - dst = special(dst, 1, dst_op->base, SZ_D); - } else { - dst = special_disp8(dst, 1, dst_op->base, dst_op->disp, SZ_D); - } - dst = setcc_r(dst, CC_C, FLAG_C); - dst = jmp(dst, dst+4); - *neq_32_off = dst - (neq_32_off+1); - } - dst = mov_ir(dst, 0, FLAG_C, SZ_B); - dst = mov_ir(dst, 1, FLAG_Z, SZ_B); - dst = mov_ir(dst, 0, FLAG_N, SZ_B); + if (inst->op == M68K_ASL) { + //ASL has Overflow flag behavior that depends on all of the bits shifted through the MSB + //Easiest way to deal with this is to shift one bit at a time + dst = mov_ir(dst, 0, FLAG_V, SZ_B); + uint8_t * loop_start = dst; if (dst_op->mode == MODE_REG_DIRECT) { - dst = xor_rr(dst, dst_op->base, dst_op->base, inst->extra.size); - } else { - dst = mov_irdisp8(dst, 0, dst_op->base, dst_op->disp, inst->extra.size); - } - } else { - if (dst_op->mode == MODE_REG_DIRECT) { - dst = shift_ir(dst, 31, dst_op->base, inst->extra.size); dst = shift_ir(dst, 1, dst_op->base, inst->extra.size); } else { - dst = shift_irdisp8(dst, 31, dst_op->base, dst_op->disp, inst->extra.size); dst = shift_irdisp8(dst, 1, dst_op->base, dst_op->disp, inst->extra.size); } + //dst = setcc_r(dst, CC_O, FLAG_V); + dst = jcc(dst, CC_NO, dst+4); + dst = mov_ir(dst, 1, FLAG_V, SZ_B); + dst = loop(dst, loop_start); + } else { + //x86 shifts modulo 32 for operand sizes less than 64-bits + //but M68K shifts modulo 64, so we need to check for large shifts here + dst = cmp_ir(dst, 32, RCX, SZ_B); + uint8_t * norm_shift_off = dst + 1; + dst = jcc(dst, CC_L, dst+2); + if (special) { + if (inst->extra.size == OPSIZE_LONG) { + uint8_t * neq_32_off = dst + 1; + dst = jcc(dst, CC_NZ, dst+2); + + //set the carry bit to the lsb + if (dst_op->mode == MODE_REG_DIRECT) { + dst = special(dst, 1, dst_op->base, SZ_D); + } else { + dst = special_disp8(dst, 1, dst_op->base, dst_op->disp, SZ_D); + } + dst = setcc_r(dst, CC_C, FLAG_C); + dst = jmp(dst, dst+4); + *neq_32_off = dst - (neq_32_off+1); + } + dst = mov_ir(dst, 0, FLAG_C, SZ_B); + dst = mov_ir(dst, 1, FLAG_Z, SZ_B); + dst = mov_ir(dst, 0, FLAG_N, SZ_B); + if (dst_op->mode == MODE_REG_DIRECT) { + dst = xor_rr(dst, dst_op->base, dst_op->base, inst->extra.size); + } else { + dst = mov_irdisp8(dst, 0, dst_op->base, dst_op->disp, inst->extra.size); + } + } else { + if (dst_op->mode == MODE_REG_DIRECT) { + dst = shift_ir(dst, 31, dst_op->base, inst->extra.size); + dst = shift_ir(dst, 1, dst_op->base, inst->extra.size); + } else { + dst = shift_irdisp8(dst, 31, dst_op->base, dst_op->disp, inst->extra.size); + dst = shift_irdisp8(dst, 1, dst_op->base, dst_op->disp, inst->extra.size); + } + } + end_off = dst+1; + dst = jmp(dst, dst+2); + *norm_shift_off = dst - (norm_shift_off+1); + if (dst_op->mode == MODE_REG_DIRECT) { + dst = shift_clr(dst, dst_op->base, inst->extra.size); + } else { + dst = shift_clrdisp8(dst, dst_op->base, dst_op->disp, inst->extra.size); + } } - end_off = dst+1; - dst = jmp(dst, dst+2); - *norm_shift_off = dst - (norm_shift_off+1); - if (dst_op->mode == MODE_REG_DIRECT) { - dst = shift_clr(dst, dst_op->base, inst->extra.size); - } else { - dst = shift_clrdisp8(dst, dst_op->base, dst_op->disp, inst->extra.size); - } - } } @@ -2702,9 +2752,14 @@ if (special && end_off) { *end_off = dst - (end_off + 1); } - dst = mov_ir(dst, 0, FLAG_V, SZ_B); //set X flag to same as C flag dst = mov_rrind(dst, FLAG_C, CONTEXT, SZ_B); + if (z_off) { + *z_off = dst - (z_off + 1); + } + if (inst->op != M68K_ASL && inst->src.addr_mode != MODE_UNUSED && !(src_op->mode == MODE_IMMED && src_op->disp == 1)) { + dst = mov_ir(dst, 0, FLAG_V, SZ_B); + } if (inst->src.addr_mode == MODE_UNUSED) { dst = m68k_save_result(inst, dst, opts); }