IBM PC早期计算机BIOS及其汇编源代码

IBM PC BIOS dated 04/24/81 is 5940 lines based on the BIOS listings in the IBM PC Technical Reference dated August 1981. The BIOS was likely built using the Intel ASM86 Macro Assembler V1.0. Notes to build with MASM 1 to 4: Line 1: $TITLE(ROM BIOS FOR IBM PERSONAL COMPUTER) to build with MASM remove the '$' Line 193: CODE SEGMENT AT 0F000H to build with MASM and LINK remove the 'AT 0F000H' LINK will not generate code for 'AT address' segments Line 539: JMP TST6 MASM generates EB 2B 90 while the BIOS has E9 2A 00 Line 647: JMP TST8 MASM generates EB 37 90 while the BIOS has E9 36 00 Line 944: JMP TST12 MASM generates EB 4B 90 while the BIOS has E9 4A 00 Line 2511: MOV SI,OFFSET J17 to match the BIOS (BE F3 ED 90) add an extra NOP after this line the original assembler generated an extra NOP due to the forward reference Line 5936: JMP RESET MASM generates a near jump instead of a far jump also LINK will not generate code for 'AT address' segments LINK will generate an .EXE file with 22 relocations. These are due to references to the CODE segment and should be F000. Unfortunately EXE2BIN will not process the EXE file as it has more than 65278 bytes of code. The BIOS code ends at FFD9, the bytes from FFDA to FFEF should be padded with FF. The VECTOR segment data should be entered at FFF0 as follows: EA 5B E0 00 F0 30 34 2F 32 34 2F 38 31 FF FF EB --- IBM PC BIOS version 2 (10/19/81) differences: Line 196: change copyright notice: DB '5700671 COPR. IBM 1981' Line 368-371: change instruction order: CMP BL,0FFH ;YES - SEE IF ALL BITS GO OFF JE C13 ; TIMER1_BITS_OFF IN AL,TIMER+1 ;READ TIMER 1 COUNT OR BL,AL ;ALL BITS ON IN TIMER Line 380: add two NOPs after this line for timing delay: OUT TIMER+3,AL Line 385: add two NOPs after this line to maintain offsets: JMP SHORT ERR01 Line 390-391: delete these lines: MOV AL,54H ;SEL TIM 1, LSB, MODE 2 OUT TIMER+3,AL ;WRITE TIMER MODE REG Line 702: move this instruction just after line 711 in POST: REP MOVSW ;MOVE VECTOR TABLE TO RAM Line 1566: correct timeout error code in comm routine: OR AH,80H ; INDICATE TIME OUT Line 3065: change timeout value in print routine: MOV BL,20 ; TIME OUT VALUE Line 5297: move this line just before line 5293 in cassette routine: MOV BX,EDGE_CNT ;BX GETS LAST EDGE COUNT Line 5510: change bottom row of character 04 (diamond): DB 010H,038H,07CH,0FEH,07CH,038H,010H,000H ; D_04 Line 5938: change BIOS release date: DB '10/19/81' ; RELEASE MARKER The VECTOR segment data should be entered at FFF0 as follows: EA 5B E0 00 F0 31 30 2F 31 39 2F 38 31 FF FF 9B --- IBM PC BIOS version 3 (10/27/82) IBM PC BIOS dated 10/27/82 is 6207 lines based on the BIOS listings in the IBM PC Technical Reference dated April 1984. The BIOS was likely built using the Intel ASM86 Macro Assembler V2.0. This BIOS must be built with ASM86, several operand constructs are used which MASM does not recognize. Line 224: CODE SEGMENT AT 0F000H to build with LINK remove the 'AT 0F000H' LINK will not generate code for 'AT address' segments LINK will generate an .EXE file with 1 relocation. This is due to a far jump to segment F000. Unfortunately EXE2BIN will not process the EXE file as it has more than 65278 bytes of code. The VECTOR segment data should be entered at FFF0 as follows: EA 5B E0 00 F0 31 30 2F 32 37 2F 38 32 FF FF 77