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Related Content: CS606 - VU Lectures, Handouts, PPT Slides, Assignments, Quizzes, Papers & Books of Compiler Construction
Three-Address Statement Types
Prior to proceeding with flow-of-control construct, here are the types of three-Address statements that we will use
- Assignment statement
x = y op z
op is a binary arithmetic or logical operation - Copy statement
x = y
value of y is assigned to x
Read more: CS606 - Compiler Construction - Lecture Handout 38
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Related Content: CS606 - VU Lectures, Handouts, PPT Slides, Assignments, Quizzes, Papers & Books of Compiler Construction
Here is the bottom-up parse of the assignment statement a = b*-c + b*-c and the syntax-directed translation into three-address code.
| Parser action | attribute | Three- address code |
| id=id ∗ –id + id ∗ –id | ||
| id=E1 ∗ –id + id ∗ –id | E1.place = b | |
| id=E1 ∗ –E2 + id ∗ –id | E2.place = c | |
| id=E1 ∗ E2 + id ∗ –id | E2.place = t1 | t1 = – c |
| id=E1 + id ∗ –id | E1.place = t2 | t2 = b∗t1 |
| id=E1 + E2 ∗ –id | E2.place = b | |
| id=E1 + E2 ∗ –E3 | E3.place = c | |
| id=E1 + E2 ∗ E3 | E3.place = t3 | t3 = – c |
| id=E1 + E2 | E2.place = t4 | t4 = b∗t3 |
| id=E1 | E1.place = t5 | t5 = t2+t4 |
| S | a = t5 |
Read more: CS606 - Compiler Construction - Lecture Handout 37
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