Dear Phillipp,
Yes, you are absolutely right: for relocatable symbols things go awry. When
attempting my previous tests on a relocatable symbol more issues can be
seen:
010050 123 _test1:
124 ; test.c: 126: __endasm;
125 ; Assembler test: loading
0xhhmmll (high, mid, low) bytes into x and a.
332211 126 pattern = 0x332211
127 ; Load mid and low.
010050 AE 00 50 [ 2] 128 ldw x, #_test1
010053 9D [ 1] 129 nop
010054 9D [ 1] 130 nop
131 ; Load low byte (xh is set to
0).
132 ; Does not seem to work with
relocatable symbol (relocation error).
010055 AE 00 11 [ 2] 133 ldw x, #<pattern
010058 9D [ 1] 134 nop
010059 9D [ 1] 135 nop
136 ; Load mid byte (xl is set to
0).
137 ; Does not seem to work with
relocatable symbol (relocation error).
01005A AE 00 22 [ 2] 138 ldw x, #>pattern
01005D 9D [ 1] 139 nop
01005E 9D [ 1] 140 nop
141 ; Load high and mid. Gives
incorrect result and overwrites next memory location.
01005F AE 80 AB [ 2] 142 ldw x, #(_test1>>8)
010062 C2 [ 1] 143 nop
010063 9D [ 1] 144 nop
145 ; Load high (xh is set to 0).
Gives incorrect result.
010064 AE 00 50 [ 2] 146 ldw x, #(_test1>>16)
010067 9D [ 1] 147 nop
010068 9D [ 1] 148 nop
149 ; Load low.
010069 A6 50 [ 1] 150 ld a, #_test1
01006B 9D [ 1] 151 nop
01006C 9D [ 1] 152 nop
153 ; Load mid (2 methods).
01006D A6 00 [ 1] 154 ld a, #(_test1>>8)
01006F 9D [ 1] 155 nop
010070 9D [ 1] 156 nop
010071 A6 00 [ 1] 157 ld a, #>_test1
010073 9D [ 1] 158 nop
010074 9D [ 1] 159 nop
160 ; Load high.
010075 A6 01 [ 1] 161 ld a, #(_test1>>16)
010077 9D [ 1] 162 nop
010078 9D [ 1] 163 nop
Still a few challenges left...
Eric
> -----Oorspronkelijk bericht-----
> Van: Philipp Klaus Krause [mailto:[email protected]]
> Verzonden: vrijdag 6 april 2018 14:24
> Aan: [email protected]
> Onderwerp: Re: [Sdcc-user] How to deal bytewise with 24-bit symbols in
> asxxx x?
>
>
> Am 06.04.2018 um 14:12 schrieb Eric Rullens:
> > Dear Philipp,
> >
> > Apologies for bumping into this conversation (and thank you
> very much for
> > all the work!), but I think the assembler does what it should do.
> >
> > Please consider the following:
> >
> > […]
> >
> > 124 ; Load high and mid.
> > 00804E AE 33 22 [ 2] 125 ldw x, #(pattern>>8)
>
> This one is the problem.
>
> void main(void)
> {
> __asm
> nop
> ldw x, #(_main >> 8)
> nop
> __endasm;
> }
>
> results in this listing (comments removed):
>
> _main:
> 000000 9D [ 1] 87 nop
> 000001 AEr00r00 [ 2] 88 ldw x, #(_main >> 8)
> 000004 9D [ 1] 89 nop
> 000005 87 [ 5] 94 retf
>
> And this binary:
>
> :04F000008200F00892
> :1DF00800AE00002707724F00005A26F9AE00002709D6F02AD700005A26F7CCF004F9
> :04F00400AC00F02547
> :06F025009DAE00F0C28761
> :00000001FF
>
> As you can see, the second nop got overwritten by 0xc2. Whenever I use
> #(sym >> 8) where a 16-bit value is expected, I see the following
> instruction being overwritten.
>
> Philipp
>
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