On Thu, 10 Feb 2005 10:08:20 -0000, Charles Dobson <[EMAIL PROTECTED]> wrote:
> I am not sure if I should post this here or on bugzilla.
post your patch in bugzilla.
Thanks,
Alex
>
> While trying to get a Silicon Motion SM722 video controller
> working with Solaris, I have discovered a problem with the
> emulation of the SHLD and SHRD (double precision shift)
> instructions of the x86 emulator.
> According to the Intel Pentium User Guide Vol 3, these
> instructions can shift upto 31 bits with both 16 and 32
> bit operands. The emulator code will only work with shifts
> of upto 15 bits for 16 bit operands.
>
> The file is
> xc/extras/x86emu/src/x86emu/prim_ops.c
>
> I have modified the two functions as below.
> I am not positive the flags are set correctly so
> would appreciated someone else to check these.
>
> u16 shld_word (u16 d, u16 fill, u8 s)
> {
> unsigned int cnt, res, cf;
>
> if (s < 32) {
> cnt = s % 32;
> if (cnt > 0) {
> if (cnt > 15) {
> res = (unsigned int)fill << (cnt - 16);
> if (cnt == 16)
> cf = d & 0x1;
> else
> cf = res & 0x10000;
> }
> else {
> res = (d << cnt) | (fill >> (16-cnt));
> cf = d & (1 << (16 - cnt));
> }
> CONDITIONAL_SET_FLAG(cf, F_CF);
> CONDITIONAL_SET_FLAG((res & 0xffff) == 0, F_ZF);
> CONDITIONAL_SET_FLAG(res & 0x8000, F_SF);
> CONDITIONAL_SET_FLAG(PARITY(res & 0xff), F_PF);
> } else {
> res = d;
> }
> if (cnt == 1) {
> CONDITIONAL_SET_FLAG((((res & 0x8000) == 0x8000) ^
> (ACCESS_FLAG(F_CF) != 0)), F_OF);
> } else {
> CLEAR_FLAG(F_OF);
> }
> } else {
> res = 0;
> CONDITIONAL_SET_FLAG((d << (s-1)) & 0x8000, F_CF);
> CLEAR_FLAG(F_OF);
> CLEAR_FLAG(F_SF);
> SET_FLAG(F_PF);
> SET_FLAG(F_ZF);
> }
> return (u16)res;
> }
>
> u16 shrd_word (u16 d, u16 fill, u8 s)
> {
> unsigned int cnt, res, cf;
>
> if (s < 32) {
> cnt = s % 32;
> if (cnt > 0) {
> if (cnt > 15) {
> if (cnt == 16)
> cf = d & 0x8000;
> else
> cf = fill & (1 << (cnt - 17));
> res = fill >> (cnt - 16);
> } else {
> cf = d & (1 << (cnt - 1));
> res = (d >> cnt) | (fill << (16 - cnt));
> }
> CONDITIONAL_SET_FLAG(cf, F_CF);
> CONDITIONAL_SET_FLAG((res & 0xffff) == 0, F_ZF);
> CONDITIONAL_SET_FLAG(res & 0x8000, F_SF);
> CONDITIONAL_SET_FLAG(PARITY(res & 0xff), F_PF);
> } else {
> res = d;
> }
>
> if (cnt == 1) {
> CONDITIONAL_SET_FLAG(XOR2(res >> 14), F_OF);
> } else {
> CLEAR_FLAG(F_OF);
> }
> } else {
> res = 0;
> CLEAR_FLAG(F_CF);
> CLEAR_FLAG(F_OF);
> SET_FLAG(F_ZF);
> CLEAR_FLAG(F_SF);
> CLEAR_FLAG(F_PF);
> }
> return (u16)res;
> }
>
> Charles Dobson.
> Concurrent Technologies Plc.
>
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