On Fri, 2005-01-28 at 18:13 -0800, Dan Malek wrote:
to assist with the alternative :-) I'd like it if we can just find a way to invoke 'mipseb-*' or 'mipsel-*' based upon the configuration chosen and let it go at that.
That would be great!
Unless I'm doing something wrong, I also have to use binutils with the 'allow_branch_to_undefined' patch.
It looks to me that the code uses bal in an attempt to be position independent. It also uses a rather complicated got loading sequence. This is IMO futile, as the rest of u-boot (especially the copy to RAM routine) isn't position independent. So you can as well just load the full address of the called routines into a temporary register and jump through the register. See the patch below.
Tom
--- start.S.jnx 2005-01-20 21:51:00.000000000 +0100 +++ start.S 2005-01-20 22:01:39.000000000 +0100 @@ -28,6 +28,35 @@ #include <asm/regdef.h> #include <asm/mipsregs.h>
+#define NEWASM + +#ifdef NEWASM + +#define BAL(x) \ + lui t0, %hi(x) ; \ + ori t0, t0, %lo(x) ; \ + jalr t0 + +#define LOADGOT \ + lui gp, %hi(_GLOBAL_OFFSET_TABLE_) ; \ + ori gp, gp, %lo(_GLOBAL_OFFSET_TABLE_) + +#else + +#define BAL(x) \ + bal x + +#define LOADGOT \ + bal 1f ; \ + nop ; \ + .word _GLOBAL_OFFSET_TABLE_ - 1f + 4 ; \ +1: ; \ + move gp, ra ; \ + lw t1, 0(ra) ; \ + add gp, t1 + +#endif +
#define RVECENT(f,n) \ b f; nop @@ -237,18 +266,18 @@ #ifdef CONFIG_INCA_IP /* Disable INCA-IP Watchdog. */ - bal disable_incaip_wdt + BAL(disable_incaip_wdt) nop #endif
/* Initialize any external memory. */ - bal memsetup + BAL(memsetup) nop
/* Initialize caches... */ - bal mips_cache_reset + BAL(mips_cache_reset) nop
/* ... and enable them. @@ -260,7 +289,7 @@ /* Set up temporary stack. */ li a0, CFG_INIT_SP_OFFSET - bal mips_cache_lock + BAL(mips_cache_lock) nop
li t0, CFG_SDRAM_BASE + CFG_INIT_SP_OFFSET @@ -268,13 +297,8 @@
/* Initialize GOT pointer. */ - bal 1f - nop - .word _GLOBAL_OFFSET_TABLE_ - 1f + 4 -1: - move gp, ra - lw t1, 0(ra) - add gp, t1 + LOADGOT + la t9, board_init_f j t9 nop