[HW] Start of high imedence operations and types #8134
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Separate high impedence from the rest of the system. This will lead to a great simplification of inout and hw.
| wrapper and read and conditional drive operations. Not having implicit `z` in | ||
| the normal types seen by most of the system greatly simplifies semantics. | ||
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| HiZ types may only be inputs to modules. |
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This could be a little confusing. Maybe add a clarification that this only refers to the SSA value flow and HiZ implicitly produces a bidirectional port?
| : HWOp<"hiZ.create", [DeclareOpInterfaceMethods<OpAsmOpInterface, ["getAsmResultNames"]>]> { | ||
| let summary = "Create a new HiZ bus"; | ||
| let description = [{ | ||
| High impedance busses must come from somewhere. Thw two options are as |
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| High impedance busses must come from somewhere. Thw two options are as | |
| High impedance busses must come from somewhere. The two options are as |
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| for (auto t : type.getPorts()) | ||
| if (t.dir != ModulePort::Direction::Input && isa<HiZType>(type)) |
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| for (auto t : type.getPorts()) | |
| if (t.dir != ModulePort::Direction::Input && isa<HiZType>(type)) | |
| for (auto p : type.getPorts()) | |
| if (p.dir != ModulePort::Direction::Input && isa<HiZType>(p.type)) |
| @@ -390,6 +390,38 @@ hw.module @SimpleConstPrintReset(in %clock: i1, in %reset: i1, in %in4: i4) { | |||
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| // CHECK-LABEL: module HIZ | |||
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| // CHECK-LABEL: module HIZ | |
| // CHECK-LABEL: module HIZC |
| to drive the bus. This behavior is resolved by simulation or physics. | ||
| }]; | ||
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| let arguments = (ins HiZType:$input, HWValueType: $value, I1:$cond); |
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From my experience, most tristate busses (QSPI, I2C, GPIO, etc.) will need independent direction control for each bit. Could we give $cond the same type as $value? This would make verilog lowering more complex though.
Alternatively, if we had some way of concatenating HiZ types, we also would not have to plumb all lines out individually.
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Separate high impedence from the rest of the system. This will lead to a great simplification of inout and hw.