On Tue, Jun 26, 2012 at 1:14 PM, 陳韋任 (Wei-Ren Chen) <che...@iis.sinica.edu.tw> wrote: >> > 0xffffffff is -1, 0x80000000 is -MAX. >> > -1/-MAX ?will raise a exception, and I've handle this.
-1 / -MAX equals 0, it's not the issue here. >> > -MAX/-1 ?will get a MAX, for max value of a register is -(-MAX)-1, so, >> > it overflowed, I didn't handle this. >> >> Actually you did this with three brcondi in the else branch. The only thing >> left is not to crash in case guest doesn't want range exception. > > So Jia need to do something like below > > /* > * if ((%ra == 0xffffffff || %rb == 0x80000000) && (sr_ove == 0)) Actually the condition that needs special care is ((%rb == 0 || %ra == 0x80000000 && %rb == 0xffffffff) && sr_ove == 0) > * goto lab3; > * > * lab3: > * compute %ra/%rb but do NOT cause host failed? This step is empty if the result is undefined, which I think is the case. > */ > tcg_gen_ori_tl(cpu_sr, cpu_sr, SR_OV); > tcg_gen_ori_tl(cpu_sr, cpu_sr, SR_CY); If we get here then the first part of condition (before && sr_ove == 0) is true. > tcg_gen_brcondi_tl(TCG_COND_NE, sr_ove, SR_OVE, lab3); > gen_exception(dc, EXCP_RANGE); > gen_set_label(lab2); > tcg_gen_div_tl(cpu_R[rd], cpu_R[ra], cpu_R[rb]); > gen_set_label(lab3); > > ??? ??? == just nothing. -- Thanks. -- Max
