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https://github.com/byteworksinc/ORCA-C.git
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Make volatile loads from IO/softswitches access exactly the byte(s) specified.
Previously, one-byte loads were typically done by reading a 16-bit value and then masking off the upper 8 bits. This is a problem when accessing softswitches or slot IO locations, because reading the subsequent byte may have some undesired effect. Now, ORCA/C will do an 8-bit read for such cases, if the volatile qualifier is used. There were also a couple optimizations that could occasionally result in not all the bytes of a larger value actually being read. These are now disabled for volatile loads that may access softswitches or IO. These changes should make ORCA/C more suitable for writing low-level software like device drivers.
This commit is contained in:
Stephen Heumann
parent
21f266c5df
commit
daff1754b2
@ -349,11 +349,12 @@
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{ }
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{ pc_ind - load indirect }
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{ }
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{ Gen1t (pc_ind, disp, type) }
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{ Gen2t (pc_ind, volatile, disp, type) }
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{ }
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{ A value of type TYPE is loaded from DISP bytes past the }
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{ address that is on the evaluation stack. The address is }
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{ removed from the stack and replaced with the value. }
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{ VOLATILE is non-zero for a volatile load, or 0 otherwise. }
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{ }
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{ }
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{ pc_ior - logical or }
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6
DAG.pas
6
DAG.pas
@ -1414,7 +1414,8 @@ case op^.opcode of {check for optimizations of this node}
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PeepHoleOptimization(opv);
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end; {if}
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end {else if}
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else if op^.left^.opcode in [pc_lod,pc_ldo,pc_ind] then begin
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else if (op^.left^.opcode in [pc_lod,pc_ldo]) or
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((op^.left^.opcode = pc_ind) and (op^.left^.r = 0)) then begin
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if fromtype.optype in [cgWord,cgUWord] then
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if totype.optype in [cgByte,cgUByte,cgWord,cgUWord] then begin
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op^.left^.optype := totype.optype;
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@ -1452,7 +1453,8 @@ case op^.opcode of {check for optimizations of this node}
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with op^.left^ do
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if opcode in [pc_slr,pc_vsr] then
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if right^.opcode = pc_ldc then
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if left^.opcode in [pc_lod,pc_ldo,pc_ind] then begin
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if (left^.opcode in [pc_lod,pc_ldo]) or
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((left^.opcode = pc_ind) and (left^.r = 0)) then begin
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lq := right^.lval;
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if long(lq).msw = 0 then
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if long(lq).lsw in [8,16,24] then begin
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@ -2756,6 +2756,7 @@ var
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et: baseTypeEnum; {temp storage for a base type}
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i: integer; {loop variable}
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isString: boolean; {was the ? : a string?}
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isVolatile: boolean; {is this a volatile op?}
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lType: typePtr; {type of operands}
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kind: typeKind; {temp type kind}
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size: longint; {size of an array element}
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@ -3146,7 +3147,7 @@ var
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Gen2t(pc_lbf, bitDisp, bitSize, tp);
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end {if}
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else
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Gen1t(pc_ind, 0, tp);
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Gen2t(pc_ind, ord(tqVolatile in expressionType^.qualifiers), 0, tp);
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if pc_l in [pc_lli,pc_lld] then
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if expressionType^.cType in [ctBool,ctFloat,ctDouble,ctLongDouble,
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ctComp] then begin
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@ -3724,6 +3725,7 @@ case tree^.token.kind of
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Gen2t(pc_lod, t1, 0, cgULong);
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Gen2t(pc_lod, t1, 0, cgULong);
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lType := expressionType^.pType;
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isVolatile := tqVolatile in lType^.qualifiers;
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if isBitField then begin
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if unsigned then
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Gen2t(pc_lbu, bitDisp, bitSize, lType^.baseType)
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@ -3731,9 +3733,9 @@ case tree^.token.kind of
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Gen2t(pc_lbf, bitDisp, bitSize, lType^.baseType);
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end {if}
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else if lType^.kind = pointerType then
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Gen1t(pc_ind, 0, cgULong)
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Gen2t(pc_ind, ord(isVolatile), 0, cgULong)
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else
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Gen1t(pc_ind, 0, lType^.baseType);
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Gen2t(pc_ind, ord(isVolatile), 0, lType^.baseType);
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end; {else}
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if tqConst in lType^.qualifiers then
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Error(93);
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@ -4481,13 +4483,14 @@ case tree^.token.kind of
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else if lType^.kind = pointerType then
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lType := lType^.pType;
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expressionType := lType;
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isVolatile := tqVolatile in lType^.qualifiers;
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if lType^.kind = scalarType then
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if lType^.baseType = cgVoid then
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Gen1t(pc_ind, 0, cgULong)
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Gen2t(pc_ind, ord(isVolatile), 0, cgULong)
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else
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Gen1t(pc_ind, 0, lType^.baseType)
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Gen2t(pc_ind, ord(isVolatile), 0, lType^.baseType)
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else if lType^.kind = pointerType then
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Gen1t(pc_ind, 0, cgULong)
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Gen2t(pc_ind, ord(isVolatile), 0, cgULong)
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else if not
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((lType^.kind in [functionType,arrayType,structType,unionType])
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or ((lType^.kind = definedType) and {handle const struct/union}
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@ -4513,6 +4516,7 @@ case tree^.token.kind of
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size := 0;
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end; {else}
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kind := expressionType^.kind;
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isVolatile := tqVolatile in expressionType^.qualifiers;
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if kind = scalarType then begin
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et := expressionType^.baseType;
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if isBitField then begin
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@ -4524,12 +4528,12 @@ case tree^.token.kind of
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Gen2t(pc_lbf, bitDisp, bitSize, et);
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end {if}
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else
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Gen1t(pc_ind, long(size).lsw, et);
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Gen2t(pc_ind, ord(isVolatile), long(size).lsw, et);
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end {if}
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else if kind = pointerType then
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Gen1t(pc_ind, long(size).lsw, cgULong)
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Gen2t(pc_ind, ord(isVolatile), long(size).lsw, cgULong)
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else if kind = enumType then
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Gen1t(pc_ind, long(size).lsw, cgWord)
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Gen2t(pc_ind, ord(isVolatile), long(size).lsw, cgWord)
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else if size <> 0 then
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Gen1t(pc_inc, long(size).lsw, cgULong);
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end {if}
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23
Gen.pas
23
Gen.pas
@ -2923,6 +2923,7 @@ var
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lQuad: quadType; {requested quad address type}
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optype: baseTypeEnum; {op^.optype}
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q: integer; {op^.q}
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volatileByte: boolean; {is this a volatile byte access?}
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begin {GenInd}
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optype := op^.optype;
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@ -3068,22 +3069,36 @@ case optype of
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cgByte,cgUByte,cgWord,cgUWord: begin
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GetPointer(op^.left);
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if gLong.where = inPointer then begin
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if q = 0 then
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volatileByte := (op^.r <> 0) and (optype in [cgByte,cgUByte]);
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if q = 0 then begin
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if volatileByte then
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GenNative(m_sep, immediate, 32, nil, 0);
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if gLong.fixedDisp then
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GenNative(m_lda_indl, direct, gLong.disp, nil, 0)
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else
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GenNative(m_lda_indly, direct, gLong.disp, nil, 0)
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GenNative(m_lda_indly, direct, gLong.disp, nil, 0);
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if volatileByte then
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GenNative(m_rep, immediate, 32, nil, 0);
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end {if}
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else
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if gLong.fixedDisp then begin
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if volatileByte then
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GenNative(m_sep, immediate, 32, nil, 0);
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GenNative(m_ldy_imm, immediate, q, nil, 0);
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GenNative(m_lda_indly, direct, gLong.disp, nil, 0)
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GenNative(m_lda_indly, direct, gLong.disp, nil, 0);
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if volatileByte then
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GenNative(m_rep, immediate, 32, nil, 0);
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end {if}
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else begin
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GenImplied(m_tya);
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GenImplied(m_clc);
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GenNative(m_adc_imm, immediate, q, nil, 0);
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GenImplied(m_tay);
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GenNative(m_lda_indly, direct, gLong.disp, nil, 0)
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if volatileByte then
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GenNative(m_sep, immediate, 32, nil, 0);
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GenNative(m_lda_indly, direct, gLong.disp, nil, 0);
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if volatileByte then
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GenNative(m_rep, immediate, 32, nil, 0);
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end; {else}
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end {if}
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else if gLong.where = localAddress then begin
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