Hi,
In binutils I need to write an offset between two symbols shifted right by 2 bits. This offset is written to the xdata section. My code currently looks like this:
exp.X_op = O_subtract; exp.X_add_symbol = symbol1; exp.X_op_symbol = symbol2; emit_expr (&exp, 2);
This works fine but obviously the result value is not shifted. Anyone have a good option is to shift the output of emit_expr at write time?
I cannot use resolve_expression because the symbols do not have correct addresses at the time this code executes.
Any help appreciated,
Zac
On 22/06/23 10:18, zac.walker@linaro.org wrote:
Hi, In binutils I need to write an offset between two symbols shifted right by 2 bits. This offset is written to the xdata section. My code currently looks like this: exp.X_op = O_subtract; exp.X_add_symbol = symbol1; exp.X_op_symbol = symbol2; emit_expr (&exp, 2); This works fine but obviously the result value is not shifted. Anyone have a good option is to shift the output of emit_expr at write time? I cannot use resolve_expression because the symbols do not have correct addresses at the time this code executes.
The 'struct expressionS' has the additional 'X_md' which is used by some targets to add extra rules for the expression. I am not very knowledge on this code, but I would expect that ld has a callback to handle the expressions prior the written.
I saw that there is a define TC_PARSE_CONS_EXPRESSION that can be used to install a hook. I just wanted to make sure I was not missing something simpler.
-----Original Message----- From: Adhemerval Zanella Netto adhemerval.zanella@linaro.org Sent: Thursday, June 22, 2023 3:36 PM To: zac.walker@linaro.org; linaro-toolchain@lists.linaro.org Subject: Re: Need emit_expr to write right shifted value.
On 22/06/23 10:18, zac.walker@linaro.org wrote:
Hi, In binutils I need to write an offset between two symbols shifted right by 2 bits. This offset is written to the xdata section. My code currently looks like this: exp.X_op = O_subtract; exp.X_add_symbol = symbol1; exp.X_op_symbol = symbol2; emit_expr (&exp, 2); This works fine but obviously the result value is not shifted. Anyone have a good option is to shift the output of emit_expr at write time? I cannot use resolve_expression because the symbols do not have correct addresses at the time this code executes.
The 'struct expressionS' has the additional 'X_md' which is used by some targets to add extra rules for the expression. I am not very knowledge on this code, but I would expect that ld has a callback to handle the expressions prior the written.
linaro-toolchain@lists.linaro.org
-
Adhemerval Zanella Netto -
zac.walker＠linaro.org