TMS320F280049: is there any assembly instruction to read GPADAT in CLA?

There is no direct TBIT equivalent in the CLA instruction set.  You would have to do an 32-bit integer read of GPADAT into a CLA register, then AND it with a mask and do a conditional test on the result.  It's pretty straightforward to do.  Something like:

MMOVI16     MAR0, #0x7FFF     ; load MAR0 with GPADAT address
MNOP
MNOP
MNOP
MNOP
MMOV32     MR1, *MAR0[0]++     ; read GPADAT into MR1 as integer
MMOVI32     MR2, #0x00000001     ; set up mask
MAND32     MR3, MR1, MR2     ; AND with bit0
MMOV32     MR2, MR0, EQ     ; conditional move (for example) based on result

Regards,

Richard