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--- en:multiasm:papc:chapter_6_7 [2025/10/22 08:08] – [BMI1 and BMI2 Instructions] ktokarz
+++ en:multiasm:papc:chapter_6_7 [2025/10/23 12:56] (current) – [BMI1 and BMI2 Instructions] ktokarz
@@ Line 283: / Line 283: @@
 The **set//cc//** instruction sets the argument to 1 if the chosen condition is met, or clears the argument if the condition is not met. The condition can be freely chosen from the set of conditions available for other instructions, for example, **cmov//cc//**. This instruction is useful to convert the result of the operation into the Boolean representation.
+The **popcnt** instruction counts the number of bits equal to "1" in a data. The applications af this instruction include genome mining, handwriting recognition, digital health workloads, and fast hamming distance counts((https://patents.google.com/patent/US8214414)).
+The **crc32** instruction implements the calculation of the cyclic redundancy check in hardware. The polynomial of the value 11EDC6F41h is fixed.
 ===== Control transfer instructions =====
 Before describing the instructions used for control transfer, we will discuss how the destination address can be calculated. The destination address is the address given to the processor to make a jump to.
@@ Line 531: / Line 536: @@
 Other instructions manipulate bits as the group name stays.
-LZCNT counts zeros from the most significant bit (MSB), while TZCNT counts from the least significant bit (LSB). For a non-zero input, LZCNT returns the number of zeros before the first 1 from the left, and TZCNT returns the number of zeros before the first 1 from the right.
+The **lzcnt** instruction counts the number of zeros in an argument starting from the most significant bit. The **tzcnt** counts zeros starting from the least significant bit. For an argument that is not zero, **lzcnt** returns the number of zeros before the first 1 from the left, and **tzcnt** gives the number of zeros before the first 1 from the right.
+The **bextr** instruction copies the number of bits from source to destination arguments starting at the chosen position. The third argument specifies the number of bits and the starting bit position. Bits 7:0 of the third operand specify the starting bit position, while bits 15:8 specify the maximum number of bits to extract, as shown in figure {{ref>bextr_instr}}.
+<figure bextr_instr>
+{{ :en:multiasm:cs:bextr.png?400 |Illustration of bit extraction instruction}}
+<caption>Illustration of bit extraction instruction</caption>
+</figure>
+The **blsi** instruction extracts the single, lowest bit set to one, as shown in figure {{ref>blsi_instr}}.
+<figure blsi_instr>
+{{ :en:multiasm:cs:blsi.png?400 |Illustration of the lowest set bit extraction instruction}}
+<caption>Illustration of lowest set bit extraction instruction</caption>
+</figure>
+The **blsmsk** instruction sets all lower bits below a first bit set to 1. It is shown in figure {{ref>blsmsk_instr}}.
+<figure blsmsk_instr>
+{{ :en:multiasm:cs:blsmsk.png?400 |Illustration of the instruction which sets all lower bits below a first bit set to 1.}}
+<caption>Illustration of the instruction which sets all lower bits below a first bit set to 1</caption>
+</figure>
+The **blsr** instruction resets (clears the bit to zero value) the lowest set bit. It is shown in figure {{ref>blsr_instr}}.
+<figure blsr_instr>
+{{ :en:multiasm:cs:blsr.png?400 |Illustration of the instruction which resets a first bit set to 1.}}
+<caption>Illustration of the instruction which resets a first bit set to 1</caption>
+</figure>
+The **bzhi** instruction resets high bits starting from the specified bit position, as shown in figure {{ref>bzhi_instr}}.
+<figure bzhi_instr>
+{{ :en:multiasm:cs:bzhi.png?400 |Illustration of the instruction which resets high bits starting from the specified bit position.}}
+<caption>Illustration of the instruction which resets high bits starting from the specified bit position</caption>
+</figure>
+The **pdep** instruction performs a parallel deposit of bits using a mask. Its behaviour is shown in figure {{ref>pdep_instr}}.
+<figure pdep_instr>
+{{ :en:multiasm:cs:pdep.png?600 |Illustration of the parallel deposit instruction}}
+<caption>Illustration of the parallel deposit instruction</caption>
+</figure>
+The **pext** instruction performs a parallel extraction of bits using a mask. Its behaviour is shown in figure {{ref>pext_instr}}.
+<figure pext_instr>
+{{ :en:multiasm:cs:pext.png?600 |Illustration of the parallel extraction instruction}}
+<caption>Illustration of the parallel extraction instruction</caption>
+</figure>
-BEXTR Contiguous bitwise extract.
-BLSI Extract lowest set bit.
-BLSMSK Set all lower bits below first set bit to 1.
-BLSR Reset lowest set bit.
-BZHI Zero high bits starting from specified bit position.
-LZCNT Count the number leading zero bits.
-PDEP Parallel deposit of bits using a mask.
-PEXT Parallel extraction of bits using a mask.
-TZCNT Count the number trailing zero bits.

en/multiasm/papc/chapter_6_7.1761120494.txt.gz · Last modified: 2025/10/22 08:08 by ktokarz