diff options
author | wdenk <wdenk> | 2003-06-27 21:31:46 +0000 |
---|---|---|
committer | wdenk <wdenk> | 2003-06-27 21:31:46 +0000 |
commit | 8bde7f776c77b343aca29b8c7b58464d915ac245 (patch) | |
tree | 20f1fd99975215e7c658454a15cdb4ed4694e2d4 /cpu/i386/sc520_asm.S | |
parent | 993cad9364c6b87ae429d1ed1130d8153f6f027e (diff) | |
download | u-boot-imx-8bde7f776c77b343aca29b8c7b58464d915ac245.zip u-boot-imx-8bde7f776c77b343aca29b8c7b58464d915ac245.tar.gz u-boot-imx-8bde7f776c77b343aca29b8c7b58464d915ac245.tar.bz2 |
* Code cleanup:
- remove trailing white space, trailing empty lines, C++ comments, etc.
- split cmd_boot.c (separate cmd_bdinfo.c and cmd_load.c)
* Patches by Kenneth Johansson, 25 Jun 2003:
- major rework of command structure
(work done mostly by Michal Cendrowski and Joakim Kristiansen)
Diffstat (limited to 'cpu/i386/sc520_asm.S')
-rw-r--r-- | cpu/i386/sc520_asm.S | 406 |
1 files changed, 203 insertions, 203 deletions
diff --git a/cpu/i386/sc520_asm.S b/cpu/i386/sc520_asm.S index 7a957c7..80464fa 100644 --- a/cpu/i386/sc520_asm.S +++ b/cpu/i386/sc520_asm.S @@ -22,21 +22,21 @@ */ /* This file is largely based on code obtned from AMD. AMD's original - * copyright is included below + * copyright is included below */ /* * ============================================================================= - * - * Copyright 1999 Advanced Micro Devices, Inc. - * - * This software is the property of Advanced Micro Devices, Inc (AMD) which - * specifically grants the user the right to modify, use and distribute this - * software provided this COPYRIGHT NOTICE is not removed or altered. All - * other rights are reserved by AMD. - * - * THE MATERIALS ARE PROVIDED "AS IS" WITHOUT ANY EXPRESS OR IMPLIED WARRANTY - * OF ANY KIND INCLUDING WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT OF + * + * Copyright 1999 Advanced Micro Devices, Inc. + * + * This software is the property of Advanced Micro Devices, Inc (AMD) which + * specifically grants the user the right to modify, use and distribute this + * software provided this COPYRIGHT NOTICE is not removed or altered. All + * other rights are reserved by AMD. + * + * THE MATERIALS ARE PROVIDED "AS IS" WITHOUT ANY EXPRESS OR IMPLIED WARRANTY + * OF ANY KIND INCLUDING WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT OF * THIRD-PARTY INTELLECTUAL PROPERTY, OR FITNESS FOR ANY PARTICULAR PURPOSE. * IN NO EVENT SHALL AMD OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER * (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF PROFITS, BUSINESS @@ -45,19 +45,19 @@ * SUCH DAMAGES. BECAUSE SOME JURSIDICTIONS PROHIBIT THE EXCLUSION OR * LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES, THE ABOVE * LIMITATION MAY NOT APPLY TO YOU. - * + * * AMD does not assume any responsibility for any errors that may appear in * the Materials nor any responsibility to support or update the Materials. * AMD retains the right to make changes to its test specifications at any * time, without notice. - * - * So that all may benefit from your experience, please report any problems - * or suggestions about this software back to AMD. Please include your name, - * company, telephone number, AMD product requiring support and question or - * problem encountered. - * - * Advanced Micro Devices, Inc. Worldwide support and contact - * Embedded Processor Division information available at: + * + * So that all may benefit from your experience, please report any problems + * or suggestions about this software back to AMD. Please include your name, + * company, telephone number, AMD product requiring support and question or + * problem encountered. + * + * Advanced Micro Devices, Inc. Worldwide support and contact + * Embedded Processor Division information available at: * Systems Engineering epd.support@amd.com * 5204 E. Ben White Blvd. -or- * Austin, TX 78741 http://www.amd.com/html/support/techsup.html @@ -66,7 +66,7 @@ /******************************************************************************* - * AUTHOR : Buddy Fey - Original. + * AUTHOR : Buddy Fey - Original. ******************************************************************************* */ @@ -140,368 +140,368 @@ * initialize dram controller registers */ .globl mem_init -mem_init: - xorw %ax,%ax - movl $DBCTL, %edi +mem_init: + xorw %ax,%ax + movl $DBCTL, %edi movb %al, (%edi) /* disable write buffer */ - movl $ECCCTL, %edi + movl $ECCCTL, %edi movb %al, (%edi) /* disable ECC */ - movl $DRCTMCTL, %edi - movb $0x1E,%al /* Set SDRAM timing for slowest */ + movl $DRCTMCTL, %edi + movb $0x1E,%al /* Set SDRAM timing for slowest */ movb %al, (%edi) /* * setup loop to do 4 external banks starting with bank 3 */ - movl $0xff000000,%eax /* enable last bank and setup */ - movl $DRCBENDADR, %edi /* ending address register */ + movl $0xff000000,%eax /* enable last bank and setup */ + movl $DRCBENDADR, %edi /* ending address register */ movl %eax, (%edi) - movl $DRCCFG, %edi /* setup */ - movw $0xbbbb,%ax /* dram config register for */ + movl $DRCCFG, %edi /* setup */ + movw $0xbbbb,%ax /* dram config register for */ movw %ax, (%edi) /* * issue a NOP to all DRAMs */ - movl $DRCCTL, %edi /* setup DRAM control register with */ - movb $0x1,%al /* Disable refresh,disable write buffer */ + movl $DRCCTL, %edi /* setup DRAM control register with */ + movb $0x1,%al /* Disable refresh,disable write buffer */ movb %al, (%edi) - movl $CACHELINESZ, %esi /* just a dummy address to write for */ + movl $CACHELINESZ, %esi /* just a dummy address to write for */ movw %ax, (%esi) /* * delay for 100 usec? 200? * ******this is a cludge for now ************* */ - movw $100,%cx -sizdelay: - loop sizdelay /* we need 100 usec here */ + movw $100,%cx +sizdelay: + loop sizdelay /* we need 100 usec here */ /***********************************************/ /* * issue all banks precharge */ - movb $0x2,%al /* All banks precharge */ + movb $0x2,%al /* All banks precharge */ movb %al, (%edi) movw %ax, (%esi) /* - * issue 2 auto refreshes to all banks + * issue 2 auto refreshes to all banks */ - movb $0x4,%al /* Auto refresh cmd */ + movb $0x4,%al /* Auto refresh cmd */ movb %al, (%edi) - movw $2,%cx -refresh1: + movw $2,%cx +refresh1: movw %ax, (%esi) - loop refresh1 + loop refresh1 /* * issue LOAD MODE REGISTER command */ - movb $0x3,%al /* Load mode register cmd */ + movb $0x3,%al /* Load mode register cmd */ movb %al, (%edi) movw %ax, (%esi) /* - * issue 8 more auto refreshes to all banks - */ - movb $0x4,%al /* Auto refresh cmd */ + * issue 8 more auto refreshes to all banks + */ + movb $0x4,%al /* Auto refresh cmd */ movb %al, (%edi) - movw $8,%cx -refresh2: + movw $8,%cx +refresh2: movw %ax, (%esi) - loop refresh2 + loop refresh2 /* - * set control register to NORMAL mode + * set control register to NORMAL mode */ - movb $0x0,%al /* Normal mode value */ + movb $0x0,%al /* Normal mode value */ movb %al, (%edi) /* * size dram starting with external bank 3 moving to external bank 0 */ - movl $0x3,%ecx /* start with external bank 3 */ + movl $0x3,%ecx /* start with external bank 3 */ -nextbank: +nextbank: /* * write col 11 wrap adr */ - movl $COL11_ADR, %esi /* set address to max col (11) wrap addr */ - movl $COL11_DATA, %eax /* pattern for max supported columns(11) */ + movl $COL11_ADR, %esi /* set address to max col (11) wrap addr */ + movl $COL11_DATA, %eax /* pattern for max supported columns(11) */ movl %eax, (%esi) /* write max col pattern at max col adr */ movl (%esi), %ebx /* optional read */ - cmpl %ebx,%eax /* to verify write */ - jnz bad_ram /* this ram is bad */ + cmpl %ebx,%eax /* to verify write */ + jnz bad_ram /* this ram is bad */ /* * write col 10 wrap adr */ - movl $COL10_ADR, %esi /* set address to 10 col wrap address */ - movl $COL10_DATA, %eax /* pattern for 10 col wrap */ + movl $COL10_ADR, %esi /* set address to 10 col wrap address */ + movl $COL10_DATA, %eax /* pattern for 10 col wrap */ movl %eax, (%esi) /* write 10 col pattern @ 10 col wrap adr */ movl (%esi), %ebx /* optional read */ - cmpl %ebx,%eax /* to verify write */ - jnz bad_ram /* this ram is bad */ + cmpl %ebx,%eax /* to verify write */ + jnz bad_ram /* this ram is bad */ /* * write col 9 wrap adr */ - movl $COL09_ADR, %esi /* set address to 9 col wrap address */ - movl $COL09_DATA, %eax /* pattern for 9 col wrap */ + movl $COL09_ADR, %esi /* set address to 9 col wrap address */ + movl $COL09_DATA, %eax /* pattern for 9 col wrap */ movl %eax, (%esi) /* write 9 col pattern @ 9 col wrap adr */ movl (%esi), %ebx /* optional read */ - cmpl %ebx,%eax /* to verify write */ - jnz bad_ram /* this ram is bad */ + cmpl %ebx,%eax /* to verify write */ + jnz bad_ram /* this ram is bad */ /* * write col 8 wrap adr */ - movl $COL08_ADR, %esi /* set address to min(8) col wrap address */ - movl $COL08_DATA, %eax /* pattern for min (8) col wrap */ + movl $COL08_ADR, %esi /* set address to min(8) col wrap address */ + movl $COL08_DATA, %eax /* pattern for min (8) col wrap */ movl %eax, (%esi) /* write min col pattern @ min col adr */ movl (%esi), %ebx /* optional read */ - cmpl %ebx,%eax /* to verify write */ - jnz bad_ram /* this ram is bad */ + cmpl %ebx,%eax /* to verify write */ + jnz bad_ram /* this ram is bad */ /* * write row 14 wrap adr */ - movl $ROW14_ADR, %esi /* set address to max row (14) wrap addr */ - movl $ROW14_DATA, %eax /* pattern for max supported rows(14) */ + movl $ROW14_ADR, %esi /* set address to max row (14) wrap addr */ + movl $ROW14_DATA, %eax /* pattern for max supported rows(14) */ movl %eax, (%esi) /* write max row pattern at max row adr */ movl (%esi), %ebx /* optional read */ - cmpl %ebx,%eax /* to verify write */ - jnz bad_ram /* this ram is bad */ + cmpl %ebx,%eax /* to verify write */ + jnz bad_ram /* this ram is bad */ /* * write row 13 wrap adr */ - movl $ROW13_ADR, %esi /* set address to 13 row wrap address */ - movl $ROW13_DATA, %eax /* pattern for 13 row wrap */ + movl $ROW13_ADR, %esi /* set address to 13 row wrap address */ + movl $ROW13_DATA, %eax /* pattern for 13 row wrap */ movl %eax, (%esi) /* write 13 row pattern @ 13 row wrap adr */ movl (%esi), %ebx /* optional read */ - cmpl %ebx,%eax /* to verify write */ - jnz bad_ram /* this ram is bad */ + cmpl %ebx,%eax /* to verify write */ + jnz bad_ram /* this ram is bad */ /* * write row 12 wrap adr */ - movl $ROW12_ADR, %esi /* set address to 12 row wrap address */ - movl $ROW12_DATA, %eax /* pattern for 12 row wrap */ + movl $ROW12_ADR, %esi /* set address to 12 row wrap address */ + movl $ROW12_DATA, %eax /* pattern for 12 row wrap */ movl %eax, (%esi) /* write 12 row pattern @ 12 row wrap adr */ movl (%esi), %ebx /* optional read */ - cmpl %ebx,%eax /* to verify write */ - jnz bad_ram /* this ram is bad */ + cmpl %ebx,%eax /* to verify write */ + jnz bad_ram /* this ram is bad */ /* * write row 11 wrap adr */ - movl $ROW11_ADR, %edi /* set address to 11 row wrap address */ - movl $ROW11_DATA, %eax /* pattern for 11 row wrap */ + movl $ROW11_ADR, %edi /* set address to 11 row wrap address */ + movl $ROW11_DATA, %eax /* pattern for 11 row wrap */ movl %eax, (%edi) /* write 11 row pattern @ 11 row wrap adr */ movl (%edi), %ebx /* optional read */ - cmpl %ebx,%eax /* to verify write */ - jnz bad_ram /* this ram is bad */ + cmpl %ebx,%eax /* to verify write */ + jnz bad_ram /* this ram is bad */ /* * write row 10 wrap adr --- this write is really to determine number of banks */ - movl $ROW10_ADR, %edi /* set address to 10 row wrap address */ - movl $ROW10_DATA, %eax /* pattern for 10 row wrap (AA) */ + movl $ROW10_ADR, %edi /* set address to 10 row wrap address */ + movl $ROW10_DATA, %eax /* pattern for 10 row wrap (AA) */ movl %eax, (%edi) /* write 10 row pattern @ 10 row wrap adr */ movl (%edi), %ebx /* optional read */ - cmpl %ebx,%eax /* to verify write */ - jnz bad_ram /* this ram is bad */ + cmpl %ebx,%eax /* to verify write */ + jnz bad_ram /* this ram is bad */ /* - * read data @ row 12 wrap adr to determine * banks, + * read data @ row 12 wrap adr to determine * banks, * and read data @ row 14 wrap adr to determine * rows. * if data @ row 12 wrap adr is not AA, 11 or 12 we have bad RAM. - * if data @ row 12 wrap == AA, we only have 2 banks, NOT 4 + * if data @ row 12 wrap == AA, we only have 2 banks, NOT 4 * if data @ row 12 wrap == 11 or 12, we have 4 banks, */ - xorw %di,%di /* value for 2 banks in DI */ - movl (%esi), %ebx /* read from 12 row wrap to check banks - * (esi is setup from the write to row 12 wrap) */ - cmpl %ebx,%eax /* check for AA pattern (eax holds the aa pattern) */ - jz only2 /* if pattern == AA, we only have 2 banks */ + xorw %di,%di /* value for 2 banks in DI */ + movl (%esi), %ebx /* read from 12 row wrap to check banks + * (esi is setup from the write to row 12 wrap) */ + cmpl %ebx,%eax /* check for AA pattern (eax holds the aa pattern) */ + jz only2 /* if pattern == AA, we only have 2 banks */ /* 4 banks */ - - movw $8,%di /* value for 4 banks in DI (BNK_CNT bit) */ - cmpl $ROW11_DATA, %ebx /* only other legitimate values are 11 */ - jz only2 - cmpl $ROW12_DATA, %ebx /* and 12 */ - jnz bad_ram /* its bad if not 11 or 12! */ - + + movw $8,%di /* value for 4 banks in DI (BNK_CNT bit) */ + cmpl $ROW11_DATA, %ebx /* only other legitimate values are 11 */ + jz only2 + cmpl $ROW12_DATA, %ebx /* and 12 */ + jnz bad_ram /* its bad if not 11 or 12! */ + /* fall through */ -only2: +only2: /* * validate row mask */ - movl $ROW14_ADR, %esi /* set address back to max row wrap addr */ + movl $ROW14_ADR, %esi /* set address back to max row wrap addr */ movl (%esi), %eax /* read actual number of rows @ row14 adr */ - cmpl $ROW11_DATA, %eax /* row must be greater than 11 pattern */ - jb bad_ram + cmpl $ROW11_DATA, %eax /* row must be greater than 11 pattern */ + jb bad_ram - cmpl $ROW14_DATA, %eax /* and row must be less than 14 pattern */ - ja bad_ram + cmpl $ROW14_DATA, %eax /* and row must be less than 14 pattern */ + ja bad_ram - cmpb %ah,%al /* verify all 4 bytes of dword same */ - jnz bad_ram - movl %eax,%ebx - shrl $16,%ebx - cmpw %bx,%ax - jnz bad_ram + cmpb %ah,%al /* verify all 4 bytes of dword same */ + jnz bad_ram + movl %eax,%ebx + shrl $16,%ebx + cmpw %bx,%ax + jnz bad_ram /* * read col 11 wrap adr for real column data value */ - movl $COL11_ADR, %esi /* set address to max col (11) wrap addr */ + movl $COL11_ADR, %esi /* set address to max col (11) wrap addr */ movl (%esi), %eax /* read real col number at max col adr */ /* * validate column data */ - cmpl $COL08_DATA, %eax /* col must be greater than 8 pattern */ - jb bad_ram - - cmpl $COL11_DATA, %eax /* and row must be less than 11 pattern */ - ja bad_ram - - subl $COL08_DATA, %eax /* normalize column data to zero */ - jc bad_ram - cmpb %ah,%al /* verify all 4 bytes of dword equal */ - jnz bad_ram - movl %eax,%edx - shrl $16,%edx - cmpw %dx,%ax - jnz bad_ram + cmpl $COL08_DATA, %eax /* col must be greater than 8 pattern */ + jb bad_ram + + cmpl $COL11_DATA, %eax /* and row must be less than 11 pattern */ + ja bad_ram + + subl $COL08_DATA, %eax /* normalize column data to zero */ + jc bad_ram + cmpb %ah,%al /* verify all 4 bytes of dword equal */ + jnz bad_ram + movl %eax,%edx + shrl $16,%edx + cmpw %dx,%ax + jnz bad_ram /* * merge bank and col data together */ - addw %di,%dx /* merge of bank and col info in dl */ + addw %di,%dx /* merge of bank and col info in dl */ /* * fix ending addr mask based upon col info */ - movb $3,%al - subb %dh,%al /* dh contains the overflow from the bank/col merge */ - movb %bl,%dh /* bl contains the row mask (aa, 07, 0f, 1f or 3f) */ - xchgw %cx,%ax /* cx = ax = 3 or 2 depending on 2 or 4 bank device */ - shrb %cl,%dh /* */ - incb %dh /* ending addr is 1 greater than real end */ - xchgw %cx,%ax /* cx is bank number again */ + movb $3,%al + subb %dh,%al /* dh contains the overflow from the bank/col merge */ + movb %bl,%dh /* bl contains the row mask (aa, 07, 0f, 1f or 3f) */ + xchgw %cx,%ax /* cx = ax = 3 or 2 depending on 2 or 4 bank device */ + shrb %cl,%dh /* */ + incb %dh /* ending addr is 1 greater than real end */ + xchgw %cx,%ax /* cx is bank number again */ /* * issue all banks precharge */ -bad_reint: - movl $DRCCTL, %esi /* setup DRAM control register with */ - movb $0x2,%al /* All banks precharge */ +bad_reint: + movl $DRCCTL, %esi /* setup DRAM control register with */ + movb $0x2,%al /* All banks precharge */ movb %al, (%esi) - movl $CACHELINESZ, %esi /* address to init read buffer */ + movl $CACHELINESZ, %esi /* address to init read buffer */ movw %ax, (%esi) /* * update ENDING ADDRESS REGISTER */ - movl $DRCBENDADR, %edi /* DRAM ending address register */ - movl %ecx,%ebx + movl $DRCBENDADR, %edi /* DRAM ending address register */ + movl %ecx,%ebx addl %ebx, %edi movb %dh, (%edi) /* * update CONFIG REGISTER */ - xorb %dh,%dh - movw $0x00f,%bx - movw %cx,%ax - shlw $2,%ax - xchgw %cx,%ax - shlw %cl,%dx - shlw %cl,%bx - notw %bx - xchgw %cx,%ax - movl $DRCCFG, %edi + xorb %dh,%dh + movw $0x00f,%bx + movw %cx,%ax + shlw $2,%ax + xchgw %cx,%ax + shlw %cl,%dx + shlw %cl,%bx + notw %bx + xchgw %cx,%ax + movl $DRCCFG, %edi mov (%edi), %ax - andw %bx,%ax - orw %dx,%ax + andw %bx,%ax + orw %dx,%ax movw %ax, (%edi) - jcxz cleanup + jcxz cleanup - decw %cx - movl %ecx,%ebx - movl $DRCBENDADR, %edi /* DRAM ending address register */ - movb $0xff,%al + decw %cx + movl %ecx,%ebx + movl $DRCBENDADR, %edi /* DRAM ending address register */ + movb $0xff,%al addl %ebx, %edi movb %al, (%edi) /* - * set control register to NORMAL mode + * set control register to NORMAL mode */ - movl $DRCCTL, %esi /* setup DRAM control register with */ - movb $0x0,%al /* Normal mode value */ + movl $DRCCTL, %esi /* setup DRAM control register with */ + movb $0x0,%al /* Normal mode value */ movb %al, (%esi) - movl $CACHELINESZ, %esi /* address to init read buffer */ + movl $CACHELINESZ, %esi /* address to init read buffer */ movw %ax, (%esi) - jmp nextbank + jmp nextbank -cleanup: - movl $DRCBENDADR, %edi /* DRAM ending address register */ - movw $4,%cx - xorw %ax,%ax -cleanuplp: +cleanup: + movl $DRCBENDADR, %edi /* DRAM ending address register */ + movw $4,%cx + xorw %ax,%ax +cleanuplp: movb (%edi), %al - orb %al,%al - jz emptybank + orb %al,%al + jz emptybank - addb %ah,%al - jns nottoomuch + addb %ah,%al + jns nottoomuch - movb $0x7f,%al -nottoomuch: - movb %al,%ah - orb $0x80,%al + movb $0x7f,%al +nottoomuch: + movb %al,%ah + orb $0x80,%al movb %al, (%edi) -emptybank: - incl %edi - loop cleanuplp +emptybank: + incl %edi + loop cleanuplp #if defined(CFG_SDRAM_CAS_LATENCY_2T) || defined(CFG_SDRAM_CAS_LATENCY_3T) /* set the CAS latency now since it is hard to do * when we run from the RAM */ movl $DRCTMCTL, %edi /* DRAM timing register */ - movb (%edi), %al + movb (%edi), %al #ifdef CFG_SDRAM_CAS_LATENCY_2T andb $0xef, %al #endif #ifdef CFG_SDRAM_CAS_LATENCY_3T orb $0x10, %al -#endif +#endif movb %al, (%edi) #endif - movl $DRCCTL, %edi /* DRAM Control register */ - movb $0x3,%al /* Load mode register cmd */ + movl $DRCCTL, %edi /* DRAM Control register */ + movb $0x3,%al /* Load mode register cmd */ movb %al, (%edi) movw %ax, (%esi) - movl $DRCCTL, %edi /* DRAM Control register */ - movb $0x18,%al /* Enable refresh and NORMAL mode */ + movl $DRCCTL, %edi /* DRAM Control register */ + movb $0x18,%al /* Enable refresh and NORMAL mode */ movb %al, (%edi) - jmp dram_done + jmp dram_done + +bad_ram: + xorl %edx,%edx + xorl %edi,%edi + jmp bad_reint -bad_ram: - xorl %edx,%edx - xorl %edi,%edi - jmp bad_reint +dram_done: -dram_done: - /* readback DRCBENDADR and return the number - * of available ram bytes in %eax */ + * of available ram bytes in %eax */ + + movl $DRCBENDADR, %edi /* DRAM ending address register */ - movl $DRCBENDADR, %edi /* DRAM ending address register */ - movl (%edi), %eax movl %eax, %ecx andl $0x80000000, %ecx jz bank2 andl $0x7f000000, %eax - shrl $2, %eax + shrl $2, %eax movl %eax, %ebx bank2: movl (%edi), %eax @@ -509,7 +509,7 @@ bank2: movl (%edi), %eax andl $0x00800000, %ecx jz bank1 andl $0x007f0000, %eax - shll $6, %eax + shll $6, %eax movl %eax, %ebx bank1: movl (%edi), %eax @@ -517,7 +517,7 @@ bank1: movl (%edi), %eax andl $0x00008000, %ecx jz bank0 andl $0x00007f00, %eax - shll $14, %eax + shll $14, %eax movl %eax, %ebx bank0: movl (%edi), %eax @@ -525,7 +525,7 @@ bank0: movl (%edi), %eax andl $0x00000080, %ecx jz done andl $0x0000007f, %eax - shll $22, %eax + shll $22, %eax movl %eax, %ebx done: movl %ebx, %eax |