Yosef Karo

“ Paragraph 11 - A routine sleep in the day in one's bed does constitute an interruption. But some say it does not, and that is our custom.
סעיף י"א - שינת קבע ביום על מטתו הוי הפסק ויש אומרים דלא הוי הפסק וכן נהגו:
Paragraph 12 - Even if one studies at night, the night is regarded as following from the previous day, so he is not required to repeat the blessing as long as he has not yet slept. ”

“ Paragraph 13 - One who rises early before daylight to study should recite the blessings of the Torah first and he does not need to repeat them when he goes to synagogue. One who rises early before daylight should recite the full order of (morning) blessings except for "who has given to the shechvi (cockerel/heart) [2] understanding..." and the scriptural section dealing with the daily sacrifice. Rather he should wait until daylight before saying these. Rema: Ideally, one should perform morning hand-washing before recite the blessings to study. ”