diff options
Diffstat (limited to 'target-cris/op_helper.c')
| -rw-r--r-- | target-cris/op_helper.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/target-cris/op_helper.c b/target-cris/op_helper.c index 51323a2..6b23980 100644 --- a/target-cris/op_helper.c +++ b/target-cris/op_helper.c @@ -243,6 +243,32 @@ void helper_rfn(void) env->pregs[PR_CCS] |= M_FLAG; } +uint32_t helper_btst(uint32_t t0, uint32_t t1, uint32_t ccs) +{ + /* FIXME: clean this up. */ + + /* des ref: + The N flag is set according to the selected bit in the dest reg. + The Z flag is set if the selected bit and all bits to the right are + zero. + The X flag is cleared. + Other flags are left untouched. + The destination reg is not affected.*/ + unsigned int fz, sbit, bset, mask, masked_t0; + + sbit = t1 & 31; + bset = !!(t0 & (1 << sbit)); + mask = sbit == 31 ? -1 : (1 << (sbit + 1)) - 1; + masked_t0 = t0 & mask; + fz = !(masked_t0 | bset); + + /* Clear the X, N and Z flags. */ + ccs = ccs & ~(X_FLAG | N_FLAG | Z_FLAG); + /* Set the N and Z flags accordingly. */ + ccs |= (bset << 3) | (fz << 2); + return ccs; +} + static void evaluate_flags_writeback(uint32_t flags) { unsigned int x, z, mask; |