[sdcc-devel] [ sdcc-Bugs-1003390 ] IRQ preamble might save wrong register bank

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Bugs item #1003390, was opened at 2004-08-04 16:32
Message generated for change (Tracker Item Submitted) made by Item Submitter
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=100599&aid=1003390&group_id=599

Category: msc51(8051) target
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Frieder Ferlemann (frief)
Assigned to: Nobody/Anonymous (nobody)
Summary: IRQ preamble might save wrong register bank

Initial Comment:
This problem only occurs if functions are declared with
the "using" keyword. (SDCC 2.4.3 #785)
Source and some generated assembly follows:


#include <8052.h>

volatile unsigned char ms;

#pragma save
#pragma nooverlay
void some_function(void) reentrant
{
    ms++;
}
#pragma restore


// IRQ preamble eventually pushes wrong register bank
here if interrupt
// occurs while register bank0 is not selected
void some_irq( void ) interrupt 1
{
    some_function();
}


void not_bank0_function() using 3
{
    unsigned char i=ms;
    while(--i)          // allocated to r2 in bank 3 (0x1a)
        ms--;
}


void main( void )
{
    while(1)
       not_bank0_function();
}





#if 0

;irq.c:16: void some_irq( void ) interrupt 1
;   -----------------------------------------
;    function some_irq
;   -----------------------------------------
_some_irq:
    push    acc
    push    b
    push    dpl
    push    dph
;
;*** pushing/setting psw should be done here?!
;
    push    (0+2)
    push    (0+3)
    push    (0+4)
    push    (0+5)
    push    (0+6)
    push    (0+7)
    push    (0+0)
    push    (0+1)
    push    psw
    mov psw,#0x00
;irq.c:18: some_function();
;     genCall
    lcall   _some_function
00101$:
    pop psw
    pop (0+1)
    pop (0+0)
    pop (0+7)
    pop (0+6)
    pop (0+5)
    pop (0+4)
    pop (0+3)
    pop (0+2)
;
;*** popping psw should be done here?!
;
    pop dph
    pop dpl
    pop b
    pop acc
    reti


#endif

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