Translation:Shulchan Aruch/Orach Chaim/89
The Mitzvah of praying Tephilat Ha'Shachar (morning prayers) begins when the sun rises. As it says "You will fear (Him) with the sun". If one prayed at the crack of dawn, and the eastern side was lit up, then one fulfilled his obligation. The time of prayer ends at the fourth hour which is a third into the day. If one forgot or erred and prayed between the fourth hour and midday, even though he did not get the reward of praying at the right time, he does fulfil the obligation of prayer.
Ramah: And after midday, it is forbidden to pray the Shacharit prayer.
Since the time of prayer is approaching, it is forbidden for someone to go to the entrance of the house of one's friend and say "Shalom" to him, since (one of) the Names of God is "Shalom". However, it is permitted to say "good morning". Even this is not permitted, except...
It is forbidden for one to carry out their needs or travel until they pray morning prayer. (There are those who are lenient and rule that after one says some of Berachot which is before Baruch she'amar (one can fulfill their needs)...and it is good to be strict on this issue). One should not eat nor drink before one prays, whether it is a weekday, Shabbas or Yom Tov.
It is permitted for a sick person to eat or drink.
One who is hungry or thirsty is considered like a sick person. If he can have Kavanah (i.e. if he can concentrate), he should pray. If he can't, he is permitted to refrain from prayers until he eats.
If one started eating before the crack of dawn, one is required to stop. According to some, one is not required to stop.
Even learning Torah is prohibited when the proper time for prayers arise. If one went to learn in a house of study
Even for learning (Torah), it is forbidden to pass the time for prayer. There are those who pray in the house of study and don't go to Synagogues.
it is permitted to get a haircut or to go take a bath (before prayers), because (Our Rabbis) only decreed (that one is not allowed to go to these places) before Mincha. when that is not at the same time as Mincha becuase it is a Mitzvah
In an emergency, like when one has to travel, one is allowed to pray at the crack of dawn. but should refrain from saying Keriat Shemah until the appropriate time. (If one can read Shema while travelling (one may), as long as he concentrates during the first verse.) (Beit Yosef quoting the Rashba). Although one does not get to have semucha geullah le'tephila, it is better that one prays at home while standing then praying at the proper time while travelling, even though (in the latter situation) one gets semucha geullah letephila