One more example: Asrock P4i65gv, AMIBIOS, Intel i865 BOOTBLK:56B1

One more example:
Asrock P4i65gv, AMIBIOS, Intel i865

BOOTBLK:56B1             ; =============== S U B R O U T I N E =======================================
BOOTBLK:56B1
BOOTBLK:56B1
BOOTBLK:56B1             SMBus_WriteBlock proc near                                  ; CODE XREF: sub_F54A6+93j
BOOTBLK:56B1                                                                         ; sub_F54A6+C0j ...
BOOTBLK:56B1 66 0F CF                    bswap   edi                                 ; Swap bytes
BOOTBLK:56B4 66 C1 C0 10                 rol     eax, 10h                            ; Rotate Left
BOOTBLK:56B8 B9 B8 0B                    mov     cx, 0BB8h
BOOTBLK:56B8
BOOTBLK:56BB
BOOTBLK:56BB             write_loop:                                                 ; CODE XREF: SMBus_WriteBlock+23j
BOOTBLK:56BB B8 FF 00                    mov     ax, 0FFh                            ; value
BOOTBLK:56BE BF C4 56                    mov     di, offset SMB_Read_Host_Status
BOOTBLK:56C1 E9 C2 00                    jmp     SMBus_io_write_SL                   ; set SMB Host Status
BOOTBLK:56C1
BOOTBLK:56C4             ; ---------------------------------------------------------------------------
BOOTBLK:56C4
BOOTBLK:56C4             SMB_Read_Host_Status:                                       ; DATA XREF: SMBus_WriteBlock+Do
BOOTBLK:56C4 E6 ED                       out     0EDh, al                            ; delay
BOOTBLK:56C6 B4 00                       mov     ah, 0                               ; reg
BOOTBLK:56C8 BF CE 56                    mov     di, offset SMB_Check_Host_Status
BOOTBLK:56CB E9 C0 00                    jmp     SMBus_io_read_SL                    ; set SMB_Host_Status
BOOTBLK:56CB
BOOTBLK:56CE             ; ---------------------------------------------------------------------------
BOOTBLK:56CE
BOOTBLK:56CE             SMB_Check_Host_Status:                                      ; DATA XREF: SMBus_WriteBlock+17o
BOOTBLK:56CE 24 0F                       and     al, 1111b                           ; Logical AND
BOOTBLK:56D0 3C 00                       cmp     al, 0                               ; No SMB errors
BOOTBLK:56D2 74 0C                       jz      short SMBus_WriteByte               ; Jump if Zero (ZF=1)
BOOTBLK:56D2
BOOTBLK:56D4 E2 E5                       loop    write_loop                          ; Loop while CX != 0
BOOTBLK:56D4
BOOTBLK:56D6 66 C1 C8 10                 ror     eax, 10h                            ; Rotate Right
BOOTBLK:56DA 66 0F CF                    bswap   edi                                 ; Swap bytes
BOOTBLK:56DD F9                          stc                                         ; Set Carry Flag
BOOTBLK:56DE FF E7                       jmp     di                                  ; Indirect Near Jump
BOOTBLK:56DE
BOOTBLK:56DE             SMBus_WriteBlock endp
BOOTBLK:56DE
BOOTBLK:56E0
BOOTBLK:56E0             ; =============== S U B R O U T I N E =======================================
BOOTBLK:56E0
BOOTBLK:56E0
BOOTBLK:56E0             SMBus_WriteByte proc near                                   ; CODE XREF: SMBus_WriteBlock+21j
BOOTBLK:56E0 B8 D2 04                    mov     ax, 4D2h                            ; reg = 0x4; // XMIT_SLVA  - Transmit Slave Address
BOOTBLK:56E0                                                                         ; value = 0xD2;
BOOTBLK:56E3 BF E9 56                    mov     di, offset SMB_Send_CMD
BOOTBLK:56E6 E9 9D 00                    jmp     SMBus_io_write_SL                   ; Jump
BOOTBLK:56E6
BOOTBLK:56E9             ; ---------------------------------------------------------------------------
BOOTBLK:56E9
BOOTBLK:56E9             SMB_Send_CMD:                                               ; DATA XREF: SMBus_WriteByte+3o
BOOTBLK:56E9 66 C1 C0 08                 rol     eax, 8                              ; Rotate Left
BOOTBLK:56ED 0C 80                       or      al, 80h                             ; value
BOOTBLK:56EF B4 03                       mov     ah, 3                               ; reg = 0x3; // HST_CMD - Host Command
BOOTBLK:56F1 BF F7 56                    mov     di, offset SMB_Send_Data
BOOTBLK:56F4 E9 8F 00                    jmp     SMBus_io_write_SL                   ; Jump
BOOTBLK:56F4
BOOTBLK:56F7             ; ---------------------------------------------------------------------------
BOOTBLK:56F7
BOOTBLK:56F7             SMB_Send_Data:                                              ; DATA XREF: SMBus_WriteByte+11o
BOOTBLK:56F7 66 C1 C0 08                 rol     eax, 8                              ; value
BOOTBLK:56FB B4 05                       mov     ah, 5                               ; reg = 0x5; // HST_D0 - Host Data 0
BOOTBLK:56FD BF 03 57                    mov     di, offset SMB_Prepare_Controller
BOOTBLK:5700 E9 83 00                    jmp     SMBus_io_write_SL                   ; Jump
BOOTBLK:5700
BOOTBLK:5703             ; ---------------------------------------------------------------------------
BOOTBLK:5703
BOOTBLK:5703             SMB_Prepare_Controller:                                     ; DATA XREF: SMBus_WriteByte+1Do
BOOTBLK:5703 B8 48 02                    mov     ax, 248h                            ; reg = 0x2; // HST_CNT  - Host Control
BOOTBLK:5703                                                                         ; value = 0x48;
BOOTBLK:5706 BF 0B 57                    mov     di, offset loc_F570B
BOOTBLK:5709 EB 7B                       jmp     short SMBus_io_write_SL             ; Jump
BOOTBLK:5709
BOOTBLK:570B             ; ---------------------------------------------------------------------------
BOOTBLK:570B
BOOTBLK:570B             loc_F570B:                                                  ; DATA XREF: SMBus_WriteByte+26o
BOOTBLK:570B B9 10 27                    mov     cx, 2710h
BOOTBLK:570B
BOOTBLK:570E
BOOTBLK:570E             delay_loop:                                                 ; CODE XREF: SMBus_WriteByte+30j
BOOTBLK:570E E6 ED                       out     0EDh, al
BOOTBLK:5710 E2 FC                       loop    delay_loop                          ; Loop while CX != 0
BOOTBLK:5710
BOOTBLK:5712 B8 FF 00                    mov     ax, 0FFh                            ; value
BOOTBLK:5715 BF 1A 57                    mov     di, offset return
BOOTBLK:5718 EB 6C                       jmp     short SMBus_io_write_SL             ; Jump
BOOTBLK:5718
BOOTBLK:571A             ; ---------------------------------------------------------------------------
BOOTBLK:571A
BOOTBLK:571A             return:                                                     ; DATA XREF: SMBus_WriteByte+35o
BOOTBLK:571A 66 0F CF                    bswap   edi                                 ; Swap bytes
BOOTBLK:571D F8                          clc                                         ; Clear Carry Flag
BOOTBLK:571E FF E7                       jmp     di                                  ; Indirect Near Jump
BOOTBLK:571E
BOOTBLK:571E             SMBus_WriteByte endp
BOOTBLK:571E
BOOTBLK:5720
BOOTBLK:5720             ; =============== S U B R O U T I N E =======================================
BOOTBLK:5720
BOOTBLK:5720
BOOTBLK:5720             SMBus_ReadBlock proc near                                   ; CODE XREF: sub_F54A6+ACj
BOOTBLK:5720 66 0F CF                    bswap   edi                                 ; Swap bytes
BOOTBLK:5723 66 C1 C0 10                 rol     eax, 10h                            ; Rotate Left
BOOTBLK:5727 B9 B8 0B                    mov     cx, 0BB8h
BOOTBLK:5727
BOOTBLK:572A
BOOTBLK:572A             read_loop:                                                  ; CODE XREF: SMBus_ReadBlock+21j
BOOTBLK:572A B8 FF 00                    mov     ax, 0FFh
BOOTBLK:572D BF 32 57                    mov     di, offset SMB_Read_Host_Status
BOOTBLK:5730 EB 54                       jmp     short SMBus_io_write_SL             ; Jump
BOOTBLK:5730
BOOTBLK:5732             ; ---------------------------------------------------------------------------
BOOTBLK:5732
BOOTBLK:5732             SMB_Read_Host_Status:                                       ; DATA XREF: SMBus_ReadBlock+Do
BOOTBLK:5732 E6 ED                       out     0EDh, al
BOOTBLK:5734 B4 00                       mov     ah, 0
BOOTBLK:5736 BF 3B 57                    mov     di, offset SMB_Check_Host_Status
BOOTBLK:5739 EB 53                       jmp     short SMBus_io_read_SL              ; Jump
BOOTBLK:5739
BOOTBLK:573B             ; ---------------------------------------------------------------------------
BOOTBLK:573B
BOOTBLK:573B             SMB_Check_Host_Status:                                      ; DATA XREF: SMBus_ReadBlock+16o
BOOTBLK:573B 24 0F                       and     al, 0Fh                             ; Logical AND
BOOTBLK:573D 3C 00                       cmp     al, 0                               ; Compare Two Operands
BOOTBLK:573F 74 0C                       jz      short SMBus_ReadByte                ; Jump if Zero (ZF=1)
BOOTBLK:573F
BOOTBLK:5741 E2 E7                       loop    read_loop                           ; Loop while CX != 0
BOOTBLK:5741
BOOTBLK:5743 66 C1 C8 10                 ror     eax, 10h                            ; Rotate Right
BOOTBLK:5747 66 0F CF                    bswap   edi                                 ; Swap bytes
BOOTBLK:574A F9                          stc                                         ; Set Carry Flag
BOOTBLK:574B FF E7                       jmp     di                                  ; Indirect Near Jump
BOOTBLK:574B
BOOTBLK:574B             SMBus_ReadBlock endp
BOOTBLK:574B
BOOTBLK:574D
BOOTBLK:574D             ; =============== S U B R O U T I N E =======================================
BOOTBLK:574D
BOOTBLK:574D
BOOTBLK:574D             SMBus_ReadByte  proc near                                   ; CODE XREF: SMBus_ReadBlock+1Fj
BOOTBLK:574D B8 D3 04                    mov     ax, 4D3h                            ; reg = 0x4; // XMIT_SLVA  - Transmit Slave Address
BOOTBLK:574D                                                                         ; value = 0xD3;
BOOTBLK:5750 BF 55 57                    mov     di, offset SMB_Send_CMD
BOOTBLK:5753 EB 31                       jmp     short SMBus_io_write_SL             ; Jump
BOOTBLK:5753
BOOTBLK:5755             ; ---------------------------------------------------------------------------
BOOTBLK:5755
BOOTBLK:5755             SMB_Send_CMD:                                               ; DATA XREF: SMBus_ReadByte+3o
BOOTBLK:5755 66 C1 C0 08                 rol     eax, 8                              ; Rotate Left
BOOTBLK:5759 0C 80                       or      al, 80h                             ; Logical Inclusive OR
BOOTBLK:575B B4 03                       mov     ah, 3                               ; reg = 0x3; // HST_CMD - Host Command
BOOTBLK:575D BF 62 57                    mov     di, offset SMB_Prepare_Controller
BOOTBLK:5760 EB 24                       jmp     short SMBus_io_write_SL             ; Jump
BOOTBLK:5760
BOOTBLK:5762             ; ---------------------------------------------------------------------------
BOOTBLK:5762
BOOTBLK:5762             SMB_Prepare_Controller:                                     ; DATA XREF: SMBus_ReadByte+10o
BOOTBLK:5762 B8 48 02                    mov     ax, 248h                            ; reg = 0x2; // HST_CNT - Host Control
BOOTBLK:5762                                                                         ; value = 0x48;
BOOTBLK:5765 BF 6A 57                    mov     di, offset loc_F576A
BOOTBLK:5768 EB 1C                       jmp     short SMBus_io_write_SL             ; Jump
BOOTBLK:5768
BOOTBLK:576A             ; ---------------------------------------------------------------------------
BOOTBLK:576A
BOOTBLK:576A             loc_F576A:                                                  ; DATA XREF: SMBus_ReadByte+18o
BOOTBLK:576A B9 30 75                    mov     cx, 7530h
BOOTBLK:576A
BOOTBLK:576D
BOOTBLK:576D             delay_loop:                                                 ; CODE XREF: SMBus_ReadByte+22j
BOOTBLK:576D E6 ED                       out     0EDh, al
BOOTBLK:576F E2 FC                       loop    delay_loop                          ; Loop while CX != 0
BOOTBLK:576F
BOOTBLK:5771 B8 FF 00                    mov     ax, 0FFh
BOOTBLK:5774 BF 79 57                    mov     di, offset SMB_Read_Data
BOOTBLK:5777 EB 0D                       jmp     short SMBus_io_write_SL             ; Jump
BOOTBLK:5777
BOOTBLK:5779             ; ---------------------------------------------------------------------------
BOOTBLK:5779
BOOTBLK:5779             SMB_Read_Data:                                              ; DATA XREF: SMBus_ReadByte+27o
BOOTBLK:5779 B4 05                       mov     ah, 5                               ; reg = 0x5; // HST_D0 - Host Data 0
BOOTBLK:577B BF 80 57                    mov     di, offset return
BOOTBLK:577E EB 0E                       jmp     short SMBus_io_read_SL              ; Jump
BOOTBLK:577E
BOOTBLK:5780             ; ---------------------------------------------------------------------------
BOOTBLK:5780
BOOTBLK:5780             return:                                                     ; DATA XREF: SMBus_ReadByte+2Eo
BOOTBLK:5780 66 0F CF                    bswap   edi                                 ; Swap bytes
BOOTBLK:5783 F8                          clc                                         ; Clear Carry Flag
BOOTBLK:5784 FF E7                       jmp     di                                  ; Indirect Near Jump
BOOTBLK:5784
BOOTBLK:5784             SMBus_ReadByte  endp
BOOTBLK:5784
BOOTBLK:5786
BOOTBLK:5786             ; =============== S U B R O U T I N E =======================================
BOOTBLK:5786
BOOTBLK:5786
BOOTBLK:5786             ; void __usercall SMBus_io_write_SL(__int8 reg<ah>, __int8 value<al>)
BOOTBLK:5786             SMBus_io_write_SL proc near                                 ; CODE XREF: SMBus_WriteBlock+10j
BOOTBLK:5786                                                                         ; SMBus_WriteByte+6j ...
BOOTBLK:5786 BA 00 04                    mov     dx, 400h
BOOTBLK:5789 8A D4                       mov     dl, ah
BOOTBLK:578B EE                          out     dx, al
BOOTBLK:578C FF E7                       jmp     di                                  ; Indirect Near Jump
BOOTBLK:578C
BOOTBLK:578C             SMBus_io_write_SL endp
BOOTBLK:578C
BOOTBLK:578E
BOOTBLK:578E             ; =============== S U B R O U T I N E =======================================
BOOTBLK:578E
BOOTBLK:578E
BOOTBLK:578E             ; __int8 __usercall SMBus_io_read_SL<al>(__int8 reg<ah>)
BOOTBLK:578E             SMBus_io_read_SL proc near                                  ; CODE XREF: SMBus_WriteBlock+1Aj
BOOTBLK:578E                                                                         ; SMBus_ReadBlock+19j ...
BOOTBLK:578E BA 00 04                    mov     dx, 400h
BOOTBLK:5791 8A D4                       mov     dl, ah
BOOTBLK:5793 EC                          in      al, dx
BOOTBLK:5794 FF E7                       jmp     di                                  ; Indirect Near Jump
BOOTBLK:5794
BOOTBLK:5794             SMBus_io_read_SL endp
BOOTBLK:5794