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MESC TOOL NEWS:
MESCT-NC79WA_1-991116D
Please take note of the following problem in using C compiler NC79WA (with assembler and integrated development environment) for the 7900 series of microcomputers.
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Versions Concerned
V.3.00 Release 1 -- V.3.10 Release 2
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Problem
In inline functions that produce stack frames, codes for recovering the previous DPR register saved on the stack cannot be created.
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Conditions
This problem occurs if any of the following three conditions is satisfied in a stack frame:
- (1)Arguments are passed to the stack
- (2)Auto variables are used
- (3)A temporary area for operations is needed
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Examples
- (1)In the case where arguments are passed to the stack
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---------------------------------------------------------------
/*C Program*/
void f(int,int);
inline void func(int i,int j)
{
f( i,j );
}
/*Codes Created*/
_func .MACRO
phd 0 <------ The previous DPR register saved on the stack
pha
tsd
sta A,DP0:1 ; i
;## # C_SRC : f( i,j );
pei DP0:5 ; j
lda A,DP0:1 ; i
jsrl $f
plx
;## # C_SRC : }
plx
.ENDM <---- The previous DPR register
remains not recovered from the stack
---------------------------------------------------------------
- (2)In the case where an auto variable is used
-
---------------------------------------------------------------
/*C Program*/
void f(int);
inline void func(void)
{
int i = 1;
f( i );
}
/*Codes Created*/
_func .MACRO
phd 0 <----- The previous DPR register saved on the stack
pha
tsd
;## # C_SRC : int i = 1;
movm.W DP0:1,#0001H ; i
;## # C_SRC : f( i );
lda A,DP0:1 ; i
jsrl $f
;## # C_SRC : }
plx
.ENDM <---- The previous DPR register
remains not recovered from the stack
---------------------------------------------------------------
- (3)In the Case where a temporary area for operations is needed
-
---------------------------------------------------------------
/*C Program*/
int i,j,k,l;
inline void func(void)
{
i = (i + j) * (k - l);
}
/*Codes Created*/
_func .MACRO
phd 0 <----- The previous DPR register saved on the stack
pha
tsd
;## # C_SRC : i = (i + j) * (k - l);
lda A,DT+:_k
sub A,DT+:_l
sta A,DP0:1 ; __TMP1
lda A,DT+:_j
add A,DT+:_i
mpys DP0:1 ; __TMP1
sta A,DT+:_i
;## # C_SRC : }
plx
.ENDM <---- The previous DPR register
remains not recovered from the stack
---------------------------------------------------------------
-
Workaround
Do not declare any function that satisfies any one of the above conditions to be an inline function.
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