__bitmap_shift_left(9)

✨ __bitmap_shift_left(9) — like, the glow-up edition ✨

okay so real talk, this is from the Kernel API Manual, and it's lowkey one of the prettiest little functions in the whole bitmap fam. bestie, we're doing a ~logical left shift~ today and honestly? it ate. 💅

🌸 NAME 🌸

__bitmap_shift_left — logical left shift of the bits in a bitmap 🎀

✨ SYNOPSIS ✨

void __bitmap_shift_left (unsigned long *dst , const unsigned long *src
, unsigned int shift , unsigned int nbits );

no cap, that's the whole signature. four args, zero drama. 🦋

💖 ARGUMENTS 💖

• dst — the destination bitmap 💫 like, where the shifted bits move in and become main character.
• src — the source bitmap 🌈 the original bits, the ones getting shifted. respect them.
• shift — shift by this many bits ✨ how far left we're yeeting everything, bit by bit.
• nbits — bitmap size, in bits 🎀 the full length of the bitmap, counted in bits, not bytes, not vibes.

👑 DESCRIPTION 👑

Shifting left (multiplying) means moving bits in the LS -> MS direction. 💫 That's it, that's the whole thing — least significant end to most significant end, bits sliding on over.

Zeros are fed into the vacated LS bit positions 🌱 (the empty spots get filled with 0s, very polite, no leftovers), and those MS bits shifted off the top are lost 💀 like, genuinely gone, off the edge of the bitmap, never coming back. so don't come crying to me about them, i warned you. 😭

lowkey important: this trailing-off-the-top thing is destructive. bits that exit at the MS end do not get saved anywhere. fr fr check your nbits before you commit. 🙈

🔥 SEE ALSO 🔥

• Kernel file ./lib/bitmap.c 🧚
• bitmap introduction(9) 🌸
• __bitmap_shift_right(9) (the twin, the mirror, the other direction 💜)
• bitmap_cut(9)
• bitmap_find_next_zero_area_off(9)
• bitmap_pos_to_ord(9)
• bitmap_remap(9)
• bitmap_bitremap(9)
• bitmap_onto(9)
• bitmap_fold(9)
• bitmap_from_arr32(9)
• bitmap_to_arr32(9)
• bitmap_from_arr64(9)
• bitmap_to_arr64(9)

okay mwah, that's the page!! 🫶 this icon lives in ./lib, it's serving October 2026 energy, and it's officially __bitmap_shift_left(9) certified slay. go shift some bits, bestie, you got this 💖✨🌟