Learning Torah prior to Davening:[1]

• When Davening in private: One who plans to Daven without a Minyan is prohibited from learning Torah from the time of Alos until he Davens.
  • Despite the above, it is permitted to learn clear Halachic rulings which contains no deep analysis before Davening, and on the contrary, it should even initially be done as it brings one to a state of joy which is required for Davening.
  • If one transgressed and began learning prior to Davening, he is nevertheless not required to stop to Daven, unless the legal time of Shema and prayer is ending.
• When Davening with a Minyan: One who plans to Daven with a Minyan may learn Torah until the Minyan begins their prayers [if the Minyan will reach Shema and Shemoneh Esrei within their legal times].
  • What topics may one learn when allowed? One may not learn the analytical parts of Torah prior to Davening, such as the analysis of a certain Halacha, as this may cause one to be distracted from concentration of his prayers and rather think about the topic during Davening. Rather one may only learn clear Halachic rulings which contain no analysis and will thus not distract him during Davening. Furthermore, learning Halacha before Davening is encouraged as it brings one to a state of joy which is required for Davening.
• If one began learning Pilpul before Davening: If one began to learn Pilpul prior to Davening then he is to make an interval and only then begin his prayers. If, however, the Minyan has already begun, then he is to Daven with them and not make an interval between his learning of Pilpul and the Davening.
• Giving a Shiur: It is permitted to give a public Shiur before Davening even if he will be Davening in private, as learning with the public is a very great Mitzvah. This however only applies if one will not be able to give this public Shiur at a different time.
• Learning Chitas, Rambam, Daf Yomi before Davening: It is permitted for one to learn Chitas, Rambam, and even Daf Yomi before Davening, if one has a set Minyan that he Davens with. Furthermore, even if he doesn’t have a set Minyan that he Davens with, and is accustomed to Daven at home, he may learn it superficially, not in great depth.

[1] Admur 89:4; 7; 93:3; 106:4; Michaber 89:6; 93:3; Aruch Hashulchan 89:27; Nimueki Orach Chaim 89; Avnei Tzedek 19; Ketzos Hashulchan 11:4; Piskeiy Teshuvos 89:23; 93:4; Igros Kodesh 17:146