[prefix] Add PCI bus:dev.fn to ROM product string

This allows multiple gPXE ROMs in a system to be disambiguated at boot
time; the PCI ID will show up in the boot menu for a BBS-compliant BIOS.

src/arch/i386/prefix/libprefix.S

  *
  * Parameters:
  *   %al : character to print
+ *   %ds:di : output buffer (or %di=0 to print to console)
  * Returns:
- *   Nothing
- * Corrupts:
- *   %ax
+ *   %ds:di : next character in output buffer (if applicable)
  *****************************************************************************
  */
 	.section ".prefix.lib"
 	.globl	print_character
 print_character:
 	/* Preserve registers */
+	pushw	%ax
 	pushw	%bx
 	pushw	%bp
-	/* Print character */
+	/* If %di is non-zero, write character to buffer and exit */
+	testw	%di, %di
+	jz	1f
+	movb	%al, %ds:(%di)
+	incw	%di
+	jmp	3f
+1:	/* Print character */
 	movw	$0x0007, %bx		/* page 0, attribute 7 (normal) */
 	movb	$0x0e, %ah		/* write char, tty mode */
 	cmpb	$0x0a, %al		/* '\n'? */
-	jne	1f
+	jne	2f
 	int	$0x10
 	movb	$0x0d, %al
-1:	int	$0x10
+2:	int	$0x10
 	/* Restore registers and return */
-	popw	%bp
+3:	popw	%bp
 	popw	%bx
+	popw	%ax
 	ret
 	.size	print_character, . - print_character
 
  *
  * Parameters:
  *   %ds:si : string to print
+ *   %ds:di : output buffer (or %di=0 to print to console)
  * Returns:
  *   %ds:si : character after terminating NUL
+ *   %ds:di : next character in output buffer (if applicable)
  *****************************************************************************
  */
 	.section ".prefix.lib"
  *   %al : byte to print
  *   %ax : word to print
  *   %eax : dword to print
+ *   %ds:di : output buffer (or %di=0 to print to console)
  * Returns:
- *   Nothing
+ *   %ds:di : next character in output buffer (if applicable)
  *****************************************************************************
  */
 	.section ".prefix.lib"
 	ret
 	.size	print_hex_nibble, . - print_hex_nibble
 
+/*****************************************************************************
+ * Utility function: print PCI bus:dev.fn
+ *
+ * Parameters:
+ *   %ax : PCI bus:dev.fn to print
+ *   %ds:di : output buffer (or %di=0 to print to console)
+ * Returns:
+ *   %ds:di : next character in output buffer (if applicable)
+ *****************************************************************************
+ */
+	.section ".prefix.lib"
+	.code16
+	.globl	print_pci_busdevfn
+print_pci_busdevfn:
+	/* Preserve registers */
+	pushw	%ax
+	/* Print bus */
+	xchgb	%al, %ah
+	call	print_hex_byte
+	/* Print ":" */
+	movb	$':', %al
+	call	print_character
+	/* Print device */
+	movb	%ah, %al
+	shrb	$3, %al
+	call	print_hex_byte
+	/* Print "." */
+	movb	$'.', %al
+	call	print_character
+	/* Print function */
+	movb	%ah, %al
+	andb	$0x07, %al
+	call	print_hex_nibble
+	/* Restore registers and return */
+	popw	%ax
+	ret
+	.size	print_pci_busdevfn, . - print_pci_busdevfn
+
 /****************************************************************************
  * pm_call (real-mode near call)
  *

src/arch/i386/prefix/pxeprefix.S

 	cld
 	/* Print welcome message */
 	movw	$10f, %si
+	xorw	%di, %di
 	call	print_message
 	.section ".prefix.data"
 10:	.asciz	"PXE->EB:"
  */
 detect_pxenv:
 	/* Signature check */
-	les	pxenv_segoff, %di
-	cmpl	$0x4e455850, %es:(%di)	/* 'PXEN' signature */
+	les	pxenv_segoff, %bx
+	cmpl	$0x4e455850, %es:(%bx)	/* 'PXEN' signature */
 	jne	no_pxenv
-	cmpw	$0x2b56, %es:4(%di)	/* 'V+' signature */
+	cmpw	$0x2b56, %es:4(%bx)	/* 'V+' signature */
 	jne	no_pxenv
 	/* Record entry point and UNDI segments */
-	pushl	%es:0x0a(%di)		/* Entry point */
+	pushl	%es:0x0a(%bx)		/* Entry point */
 	popl	entry_segoff
-	pushw	%es:0x24(%di)		/* UNDI code segment */
-	pushw	%es:0x26(%di)		/* UNDI code size */
+	pushw	%es:0x24(%bx)		/* UNDI code segment */
+	pushw	%es:0x26(%bx)		/* UNDI code size */
 	popl	undi_code_segoff
-	pushw	%es:0x20(%di)		/* UNDI data segment */
-	pushw	%es:0x22(%di)		/* UNDI data size */
+	pushw	%es:0x20(%bx)		/* UNDI data segment */
+	pushw	%es:0x22(%bx)		/* UNDI data size */
 	popl	undi_data_segoff
 	/* Print "PXENV+ at <address>" */
 	movw	$10f, %si
 	call	print_message
-	movw	%bx, %di
 	call	print_segoff
 	movb	$',', %al
 	call	print_character
  */
 detect_ppxe:
 	/* Signature check */
-	les	ppxe_segoff, %di
-	cmpl	$0x45585021, %es:(%di)	/* '!PXE' signature */
+	les	ppxe_segoff, %bx
+	cmpl	$0x45585021, %es:(%bx)	/* '!PXE' signature */
 	jne	no_ppxe
 	/* Record structure address, entry point, and UNDI segments */
 	pushw	%es
 	popw	ppxe_segment
-	movw	%di, ppxe_offset
-	pushl	%es:0x10(%di)		/* Entry point */
+	movw	%bx, ppxe_offset
+	pushl	%es:0x10(%bx)		/* Entry point */
 	popl	entry_segoff
-	pushw	%es:0x30(%di)		/* UNDI code segment */
-	pushw	%es:0x36(%di)		/* UNDI code size */
+	pushw	%es:0x30(%bx)		/* UNDI code segment */
+	pushw	%es:0x36(%bx)		/* UNDI code size */
 	popl	undi_code_segoff
-	pushw	%es:0x28(%di)		/* UNDI data segment */
-	pushw	%es:0x2e(%di)		/* UNDI data size */
+	pushw	%es:0x28(%bx)		/* UNDI data segment */
+	pushw	%es:0x2e(%bx)		/* UNDI data size */
 	popl	undi_data_segoff
 	/* Print "!PXE at <address>" */
 	movw	$10f, %si
 	/* Print entry point */
 	movw	$10f, %si
 	call	print_message
-	les	entry_segoff, %di
+	les	entry_segoff, %bx
 	call	print_segoff
 	.section ".prefix.data"
 10:	.asciz	" entry point at "
 	/* Print UNDI code segment */
 	movw	$10f, %si
 	call	print_message
-	les	undi_code_segoff, %di
+	les	undi_code_segoff, %bx
 	call	print_segoff
 	.section ".prefix.data"
 10:	.asciz	"\n         UNDI code segment "
 	/* Print UNDI data segment */
 	movw	$10f, %si
 	call	print_message
-	les	undi_data_segoff, %di
+	les	undi_data_segoff, %bx
 	call	print_segoff
 	.section ".prefix.data"
 10:	.asciz	", data segment "
 	call	print_pxe_error
 	jmp	99f
 1:	/* Free base memory used by PXE base code */
-	movw	%fs:(0x13), %si
-	movw	undi_fbms_start, %di
+	movw	undi_fbms_start, %ax
+	movw	%fs:(0x13), %bx
 	call	free_basemem
 99:
 
 	call	print_pxe_error
 	jmp	99f
 1:	/* Free base memory used by UNDI */
-	movw	undi_fbms_start, %si
-	movw	undi_fbms_end, %di
+	movw	undi_fbms_end, %ax
+	movw	undi_fbms_start, %bx
 	call	free_basemem
 	/* Clear UNDI_FL_STARTED */
 	andw	$~UNDI_FL_STARTED, flags
  * Subroutine: print segment:offset address
  *
  * Parameters:
- *   %es:%di : segment:offset address to print
+ *   %es:%bx : segment:offset address to print
+ *   %ds:di : output buffer (or %di=0 to print to console)
  * Returns:
- *   Nothing
+ *   %ds:di : next character in output buffer (if applicable)
  *****************************************************************************
  */
 print_segoff:
 	call	print_hex_word
 	movb	$':', %al
 	call	print_character
-	movw	%di, %ax
+	movw	%bx, %ax
 	call	print_hex_word
 	/* Restore registers and return */
 	popw	%ax
  *
  * Parameters:
  *   %ax : word to print
+ *   %ds:di : output buffer (or %di=0 to print to console)
  * Returns:
- *   Nothing
+ *   %ds:di : next character in output buffer (if applicable)
  *****************************************************************************
  */
 print_word:
 	popw	%ax
 	ret
 	
-/*****************************************************************************
- * Subroutine: print PCI bus:dev.fn
- *
- * Parameters:
- *   %ax : PCI bus:dev.fn to print
- * Returns:
- *   Nothing
- *****************************************************************************
- */
-print_pci_busdevfn:
-	/* Preserve registers */
-	pushw	%ax
-	/* Print bus */
-	xchgb	%al, %ah
-	call	print_hex_byte
-	/* Print ":" */
-	movb	$':', %al
-	call	print_character
-	/* Print device */
-	movb	%ah, %al
-	shrb	$3, %al
-	call	print_hex_byte
-	/* Print "." */
-	movb	$'.', %al
-	call	print_character
-	/* Print function */
-	movb	%ah, %al
-	andb	$0x07, %al
-	call	print_hex_nibble
-	/* Restore registers and return */
-	popw	%ax
-	ret	
-
 /*****************************************************************************
  * Subroutine: zero 1kB block of base memory
  *
  * Parameters:
- *   %si : block to zero (in kB)
+ *   %bx : block to zero (in kB)
  * Returns:
  *   Nothing
  *****************************************************************************
 	pushw	%di
 	pushw	%es
 	/* Zero block */
-	movw	%si, %ax
+	movw	%bx, %ax
 	shlw	$6, %ax
 	movw	%ax, %es
 	movw	$0x400, %cx
  * Subroutine: free and zero base memory
  *
  * Parameters:
- *   %si : Expected current free base memory counter (in kB)
- *   %di : Desired new free base memory counter (in kB)
+ *   %ax : Desired new free base memory counter (in kB)
+ *   %bx : Expected current free base memory counter (in kB)
  *   %fs : BIOS data segment (0x40)
  * Returns:
- *   %ax : Actual new free base memory counter (in kB)
+ *   None
  *
- * The base memory from %si kB to %di kB is unconditionally zeroed.
+ * The base memory from %bx kB to %ax kB is unconditionally zeroed.
  * It will be freed if and only if the expected current free base
- * memory counter (%si) matches the actual current free base memory
+ * memory counter (%bx) matches the actual current free base memory
  * counter in 0x40:0x13; if this does not match then the memory will
  * be leaked.
  *****************************************************************************
  */
 free_basemem:
 	/* Zero base memory */
-	pushw	%si
-1:	cmpw	%si, %di
+	pushw	%bx
+1:	cmpw	%bx, %ax
 	je	2f
 	call	zero_kb
-	incw	%si
+	incw	%bx
 	jmp	1b
-2:	popw	%si
+2:	popw	%bx
 	/* Free base memory */
-	movw	%fs:(0x13), %ax		/* Current FBMS to %ax */
-	cmpw	%ax, %si		/* Update FBMS only if "old" value  */
+	cmpw	%fs:(0x13), %bx		/* Update FBMS only if "old" value  */
 	jne	1f			/* is correct			    */
-	movw	%di, %ax
 1:	movw	%ax, %fs:(0x13)
 	ret
 

src/arch/i386/prefix/romprefix.S

 	.equ pnpheader_len, . - pnpheader
 	.size pnpheader, . - pnpheader
 
+/* Manufacturer string */
 mfgstr:
 	.asciz	"http://etherboot.org"
 	.size mfgstr, . - mfgstr
+
+/* Product string
+ *
+ * Defaults to "gPXE".  If the ROM image is writable at initialisation
+ * time, it will be filled in to include the PCI bus:dev.fn number of
+ * the card as well.
+ */
 prodstr:
-	.asciz	"gPXE"
+	.ascii	"gPXE"
+prodstr_separator:
+	.byte	0
+	.ascii	"(PCI "
+prodstr_pci_id:
+	.asciz	"xx:xx.x)"		/* Filled in by init code */
 	.size prodstr, . - prodstr
 	
 undiheader:
 	cld
 	pushw	%cs
 	popw	%ds
+	movw	%di, %bx
+	xorw	%di, %di
 	/* Print message as early as possible */
 	movw	$init_message, %si
 	call	print_message
+	call	print_pci_busdevfn
+	/* Fill in product name string, if possible */
+	movw	$prodstr_pci_id, %di
+	call	print_pci_busdevfn
+	movb	$' ', prodstr_separator
+	xorw	%di, %di
 	/* Check for PnP BIOS */
-	testw	$0x0f, %di	/* PnP signature must be aligned - bochs    */
+	testw	$0x0f, %bx	/* PnP signature must be aligned - bochs    */
 	jnz	hook_int19	/* uses unalignment to indicate 'fake' PnP. */
-	cmpl	$PNP_SIGNATURE, %es:0(%di)
+	cmpl	$PNP_SIGNATURE, %es:0(%bx)
 	jne	hook_int19
 	/* Is PnP: print PnP message */
 	movw	$init_message_pnp, %si
 	call	print_message
-	xchgw	%bx, %bx
 	/* Check for BBS */
-	pushw	%es:0x1b(%di)	/* Real-mode data segment */
+	pushw	%es:0x1b(%bx)	/* Real-mode data segment */
 	pushw	%ds		/* &(bbs_version) */
 	pushw	$bbs_version
 	pushw	$PNP_GET_BBS_VERSION
-	lcall	*%es:0xd(%di)
+	lcall	*%es:0xd(%bx)
 	addw	$8, %sp
 	testw	%ax, %ax
 	jne	hook_int19
 	popl	%es:( 0x19 * 4 )
 hook_bbs:
 	/* Check for PMM */
-	movw	$( 0xe000 - 1 ), %di
+	movw	$( 0xe00 - 1 ), %bx
 pmm_scan:
-	incw	%di
+	incw	%bx
 	jz	no_pmm
-	movw	%di, %es
+	movw	%bx, %es
 	cmpl	$PMM_SIGNATURE, %es:0
 	jne	pmm_scan
-	xorw	%bx, %bx
+	xorw	%dx, %dx
 	xorw	%si, %si
 	movzbw	%es:5, %cx
 1:	es lodsb
-	addb	%al, %bl
+	addb	%al, %dl
 	loop	1b
 	jnz	pmm_scan
 	/* PMM found: print PMM message */
 	.size init, . - init
 
 init_message:
-	.asciz	"gPXE (http://etherboot.org) -"
+	.asciz	"gPXE (http://etherboot.org) - PCI "
 	.size	init_message, . - init_message
 init_message_pnp:
 	.asciz	" PnP"
 
 	/* Print message as soon as possible */
 	movw	$exec_message, %si
+	xorw	%di, %di
 	call	print_message
 
 	/* Store magic word on BIOS stack and remember BIOS %ss:sp */