mirror of https://github.com/hsoft/collapseos.git
264 lines
5.4 KiB
NASM
264 lines
5.4 KiB
NASM
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; Same thing as instr.asm, but for AVR instructions
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; *** Instructions table ***
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; List of mnemonic names separated by a null terminator. Their index in the
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; list is their ID. Unlike in zasm, not all mnemonics have constant associated
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; to it because it's generally not needed. This list is grouped by argument
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; categories, and then alphabetically. Categories are ordered so that the 8bit
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; opcodes come first, then the 16bit ones. 0xff ends the chain
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instrNames:
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; Rd(5) + Rr(5)
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.equ I_ADC 0
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.db "ADC", 0
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.db "ADD", 0
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.db "AND", 0
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.db "CLR", 0
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.db "CP", 0
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.db "CPC", 0
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.db "CPSE", 0
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.db "EOR", 0
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.db "MOV", 0
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.db "MUL", 0
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.db "OR", 0
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.db "SBC", 0
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.db "SUB", 0
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; no arg
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.equ I_BREAK 13
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.db "BREAK", 0
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.db "CLC", 0
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.db "CLH", 0
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.db "CLI", 0
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.db "CLN", 0
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.db "CLS", 0
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.db "CLT", 0
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.db "CLV", 0
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.db "CLZ", 0
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.db "EICALL", 0
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.db "EIJMP", 0
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.db "ICALL", 0
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.db "IJMP", 0
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.db "NOP", 0
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.db "RET", 0
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.db "RETI", 0
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.db "SEC", 0
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.db "SEH", 0
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.db "SEI", 0
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.db "SEN", 0
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.db "SES", 0
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.db "SET", 0
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.db "SEV", 0
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.db "SEZ", 0
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.db "SLEEP", 0
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.db "WDR", 0
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; Rd(5)
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.equ I_ASR 39
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.db "ASR", 0
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.db "COM", 0
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.db "DEC", 0
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.db "INC", 0
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.db "LAC", 0
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.db "LAS", 0
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.db "LAT", 0
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.db "LSR", 0
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.db "NEG", 0
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.db "POP", 0
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.db "PUSH", 0
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.db "ROR", 0
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.db "SWAP", 0
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.db "XCH", 0
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.db 0xff
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; 8-bit constant masks associated with each instruction. In the same order as
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; in instrNames
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instrUpMasks1:
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; Rd(5) + Rd(5): XXXXXXrd ddddrrrr
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.db 0b00011100 ; ADC
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.db 0b00001100 ; ADD
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.db 0b00100000 ; AND
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.db 0b00100100 ; CLR
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.db 0b00010100 ; CP
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.db 0b00000100 ; CPC
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.db 0b00010000 ; CPSE
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.db 0b00100100 ; EOR
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.db 0b00101100 ; MOV
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.db 0b10011100 ; MUL
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.db 0b00101000 ; OR
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.db 0b00001000 ; SBC
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.db 0b00011000 ; SUB
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; 16-bit constant masks associated with each instruction. In the same order as
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; in instrNames
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instrUpMasks2:
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; no arg
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.db 0b10010101, 0b10011000 ; BREAK
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.db 0b10010100, 0b10001000 ; CLC
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.db 0b10010100, 0b11011000 ; CLH
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.db 0b10010100, 0b11111000 ; CLI
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.db 0b10010100, 0b10101000 ; CLN
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.db 0b10010100, 0b11001000 ; CLS
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.db 0b10010100, 0b11101000 ; CLT
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.db 0b10010100, 0b10111000 ; CLV
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.db 0b10010100, 0b10011000 ; CLZ
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.db 0b10010101, 0b00011001 ; EICALL
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.db 0b10010100, 0b00011001 ; EIJMP
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.db 0b10010101, 0b00001001 ; ICALL
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.db 0b10010100, 0b00001001 ; IJMP
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.db 0b00000000, 0b00000000 ; NOP
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.db 0b10010101, 0b00001000 ; RET
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.db 0b10010101, 0b00011000 ; RETI
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.db 0b10010100, 0b00001000 ; SEC
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.db 0b10010100, 0b01011000 ; SEH
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.db 0b10010100, 0b01111000 ; SEI
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.db 0b10010100, 0b00101000 ; SEN
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.db 0b10010100, 0b01001000 ; SES
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.db 0b10010100, 0b01101000 ; SET
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.db 0b10010100, 0b00111000 ; SEV
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.db 0b10010100, 0b00011000 ; SEZ
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.db 0b10010101, 0b10001000 ; SLEEP
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.db 0b10010101, 0b10101000 ; WDR
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; Rd(5): XXXXXXXd ddddXXXX
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.db 0b10010100, 0b00000101 ; ASR
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.db 0b10010100, 0b00000000 ; COM
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.db 0b10010100, 0b00001010 ; DEC
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.db 0b10010100, 0b00000011 ; INC
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.db 0b10010010, 0b00000110 ; LAC
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.db 0b10010010, 0b00000101 ; LAS
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.db 0b10010010, 0b00000111 ; LAT
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.db 0b10010100, 0b00000110 ; LSR
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.db 0b10010100, 0b00000001 ; NEG
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.db 0b10010000, 0b00001111 ; POP
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.db 0b10010010, 0b00001111 ; PUSH
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.db 0b10010100, 0b00000111 ; ROR
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.db 0b10010100, 0b00000010 ; SWAP
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.db 0b10010010, 0b00000100 ; XCH
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; Same signature as getInstID in instr.asm
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; Reads string in (HL) and returns the corresponding ID (I_*) in A. Sets Z if
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; there's a match.
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getInstID:
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push bc
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push hl
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push de
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ex de, hl ; DE makes a better needle
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; haystack. -1 because we inc HL at the beginning of the loop
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ld hl, instrNames-1
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ld b, 0xff ; index counter
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.loop:
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inc b
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inc hl
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ld a, (hl)
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inc a ; check if 0xff
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jr z, .notFound
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call strcmpIN
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jr nz, .loop
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; found!
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ld a, b ; index
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cp a ; ensure Z
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.end:
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pop de
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pop hl
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pop bc
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ret
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.notFound:
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dec a ; unset Z
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jr .end
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; Same signature as parseInstruction in instr.asm
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; Parse instruction specified in A (I_* const) with args in I/O and write
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; resulting opcode(s) in I/O.
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; Sets Z on success. On error, A contains an error code (ERR_*)
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parseInstruction:
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; BC, during .spit, is ORred to the spitted opcode.
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ld bc, 0
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cp I_BREAK
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jr c, .spitRd5Rr5
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cp I_ASR
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jr c, .spitNoArg
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; spitRd5
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ld d, a ; save A for later
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call .readR5
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ret nz
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call .placeRd
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ld a, d ; restore A
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; continue to .spitNoArg
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.spitNoArg:
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call .getUp2
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jr .spit
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.spitRd5Rr5:
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ld d, a ; save A for later
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call .readR5
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ret nz
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call .placeRd
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call readComma
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call .readR5
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ret nz
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push af ; --> lvl 1
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; let's start with the 4 lower bits
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and 0xf
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or c
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; We now have our LSB in A. Let's spit it now.
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call ioPutB
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pop af ; <-- lvl 1
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; and now that last high bit, currently bit 4, which must become bit 1
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and 0b00010000
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rra \ rra \ rra
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or b
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ld b, a
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ld a, d ; restore A
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ld hl, instrUpMasks1
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call addHL
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; now that's our MSB
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jr .spitMSB
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.spit:
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; LSB is spit *before* MSB
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inc hl
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ld a, (hl)
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or c
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call ioPutB
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dec hl
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.spitMSB:
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ld a, (hl)
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or b
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call ioPutB
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xor a ; ensure Z, set success
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ret
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; local routines
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; place number in A in BC at position .......d dddd....
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; BC is assumed to be 0
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.placeRd:
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sla a \ rla \ rla \ rla ; last RLA might set carry
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rl b
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ld c, a
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ret
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; Fetch a 16-bit upcode specified by instr index in A and set that upcode in HL
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.getUp2:
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sub I_BREAK
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sla a ; A * 2
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ld hl, instrUpMasks2
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jp addHL
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; read a rXX argument and return register number in A.
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; Set Z for success.
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.readR5:
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call readWord
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ld a, (hl)
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call upcase
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cp 'R'
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ret nz ; not a register
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inc hl
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call parseDecimal
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ret nz
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push ix \ pop hl
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ld a, h
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or a
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ret nz ; should be zero
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ld a, l
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cp 32
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jp nc, unsetZ ; must be < 32
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; we're good!
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cp a ; ensure Z
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ret
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