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std_logic std_logic_vector unsigned signed integer boolean signal variable constant array type
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Sequential Statements
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numeric_std conversion to_unsigned to_signed resize addition unsigned subtraction signed shift_left shift_right concatenation slice
FSM & RTL
state enum next-state logic Moore output Mealy output reset synchronous reset asynchronous clock enable counter shift register register file
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VHDL / Numeric Logic

subtraction signed

Learn subtraction signed in VHDL through a focused explanation, a dedicated construct-specific example, an engineering boundary, and a mastery check.

10 min read • Intermediate

subtraction signed is an atomic VHDL topic inside Numeric Logic. This lesson focuses on how the subtraction signed construct is written, what it changes, and when it is the right tool.

Trace the example line by line. Identify the exact syntax for subtraction signed, the input state before it runs, and the resulting value, control flow, database state, hardware behavior, or runtime effect afterward. Neighboring lessons use different constructs rather than renamed copies of this one.

Topic-specific example

vhdl-06-06-subtraction-signed.vhd
vhdl Try It Live 
diff <= resize(a,diff'length) - resize(b,diff'length);
Edge case / engineering note

For subtraction signed, test the boundary that belongs to this exact feature rather than a generic failure case. Check invalid or empty input, NULL/unknown state, numeric limits, transaction or exception behavior, synthesis/runtime constraints, ownership/permission rules, or backtracking/control-flow effects where they apply.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

subtraction signed Mastery Check →
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