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avra: a little code deduplication

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This commit is contained in:
Virgil Dupras 2019-12-15 18:52:00 -05:00
parent e9c692ed50
commit 52359a4e42
1 changed files with 42 additions and 49 deletions
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91
apps/zasm/avr.asm
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@ -134,23 +134,23 @@ instrNames:
; In the same order as in instrNames
instrTbl:
; Rd(5) + Rd(5) (0x02) and Rd(5) + bit (0x05) (same processing)
.db 0x02, 0b00011100, 0x00 ; ADC
.db 0x02, 0b00001100, 0x00 ; ADD
.db 0x02, 0b00100000, 0x00 ; AND
.db 0x05, 0b11111000, 0x00 ; BLD
.db 0x05, 0b11111010, 0x00 ; BST
.db 0x41, 0b00100100, 0x00 ; CLR (Rr copies Rd)
.db 0x02, 0b00010100, 0x00 ; CP
.db 0x02, 0b00000100, 0x00 ; CPC
.db 0x02, 0b00010000, 0x00 ; CPSE
.db 0x02, 0b00100100, 0x00 ; EOR
.db 0x02, 0b00101100, 0x00 ; MOV
.db 0x02, 0b10011100, 0x00 ; MUL
.db 0x02, 0b00101000, 0x00 ; OR
.db 0x02, 0b00001000, 0x00 ; SBC
.db 0x05, 0b11111100, 0x00 ; SBRC
.db 0x05, 0b11111110, 0x00 ; SBRS
.db 0x02, 0b00011000, 0x00 ; SUB
.db 0x02, 0b00011100, 0x00 ; ADC Rd, Rr
.db 0x02, 0b00001100, 0x00 ; ADD Rd, Rr
.db 0x02, 0b00100000, 0x00 ; AND Rd, Rr
.db 0x05, 0b11111000, 0x00 ; BLD Rd, b
.db 0x05, 0b11111010, 0x00 ; BST Rd, b
.db 0x41, 0b00100100, 0x00 ; CLR Rd (Bit 6)
.db 0x02, 0b00010100, 0x00 ; CP Rd, Rr
.db 0x02, 0b00000100, 0x00 ; CPC Rd, Rr
.db 0x02, 0b00010000, 0x00 ; CPSE Rd, Rr
.db 0x02, 0b00100100, 0x00 ; EOR Rd, Rr
.db 0x02, 0b00101100, 0x00 ; MOV Rd, Rr
.db 0x02, 0b10011100, 0x00 ; MUL Rd, Rr
.db 0x02, 0b00101000, 0x00 ; OR Rd, Rr
.db 0x02, 0b00001000, 0x00 ; SBC Rd, Rr
.db 0x05, 0b11111100, 0x00 ; SBRC Rd, b
.db 0x05, 0b11111110, 0x00 ; SBRS Rd, b
.db 0x02, 0b00011000, 0x00 ; SUB Rd, Rr
; Rd(4) + K(8): XXXXKKKK ddddKKKK
.db 0x04, 0b01110000, 0x00 ; ANDI
.db 0x04, 0b00110000, 0x00 ; CPI
@ -164,7 +164,7 @@ instrTbl:
.db 0x00, 0b11000000, 0x00 ; RJMP
; IN and OUT
.db 0x07, 0b10110000, 0x00 ; IN
.db 0x87, 0b10111000, 0x00 ; OUT (args reversed)
.db 0x87, 0b10111000, 0x00 ; OUT (Bit 7)
; no arg
.db 0x00, 0b10010101, 0b10011000 ; BREAK
.db 0x00, 0b10010100, 0b10001000 ; CLC
@ -304,43 +304,20 @@ parseInstruction:
cp I_ASR
jp c, .spit ; no arg
; spitRd5
ld a, h
call .placeRd
jp .spit
.spitRd5Rr5:
; This is used for both Rd(5) + Rr(5) and Rd(5) + bit because the same
; logic works for both cases.
ld a, h
call .placeRd
ld a, l
; let's start with the 4 lower bits
and 0xf
or c
; We now have our LSB in A. Let's spit it now.
call ioPutB
ld a, l
; and now that last high bit, currently bit 4, which must become bit 1
and 0b00010000
rra \ rra \ rra
or b
ld b, a
jp .spitMSB
call .placeRr
jr .spit
.spitRdK8:
ld a, h ; Rd
call .placeRd
ld a, l ; K
; let's start with the 4 lower bits
and 0xf
or c
; We now have our LSB in A. Let's spit it now.
call ioPutB
ld a, l
; and now those high 4 bits
and 0xf0
rra \ rra \ rra \ rra
ld b, a
jp .spitMSB
call .placeRr
rr b ; K(8) start at B's 1st bit, not 2nd
jr .spit
.spitK12:
; Let's deal with the upcode constant before we destroy IX below
@ -373,7 +350,6 @@ parseInstruction:
.spitINOUT:
; Rd in H, A in L
ld a, h
call .placeRd
ld a, l
and 0xf
@ -453,12 +429,29 @@ parseInstruction:
jr .spitBR2
; local routines
; place number in A in BC at position .......d dddd....
; place number in H in BC at position .......d dddd....
; BC is assumed to be 0
.placeRd:
sla a \ rla \ rla \ rla ; last RLA might set carry
sla h \ rl h \ rl h \ rl h ; last RL H might set carry
rl b
ld c, h
ret
; place number in L in BC at position ...rrrr. ....rrrr
; BC is assumed to be either 0 or to be set by .placeRd, that is, that the
; high 4 bits of C and lowest bit of B will be preserved.
.placeRr:
; let's start with the 4 lower bits
ld a, l
and 0x0f
or c
ld c, a
ld a, l
; and now those high 4 bits which go in B.
and 0xf0
rra \ rra \ rra
or b
ld b, a
ret
.swapHL: