initial commit

1 files changed, 75 insertions, 0 deletions

diff --git a/notes b/notes
new file mode 100644
index 0000000..294e217
--- /dev/null
+++ b/notes
@@ -0,0 +1,75 @@
+ops:
+15   14   13   12   11   10   9    8    7    6    5    4    3    2    1    0
+0  | 0  | 0  | 1  | 0  | 0  | opcode       | bw | ad      | dest              |
+0  | 0  | 1  | cond         | pc-offset                                       |
+opcode            | source            | ad | bw | as      | dest              |
+
+bw = 1 for byte ops, 0 for word ops
+
+oneop
+000 RRC 9-bit rotate through carry
+001 SWPB - swap 8-bit halves. no byte form
+010 RRA(.B) - arithmetic right shift
+011 SXT sign extend 8 bits to 16 bits. no byte form
+100 PUSH(.B) - push byte still decrements sp by 2
+101 CALL - get operand. push PC, PC = operand. no byte form. hard to do PC-relative call
+110 RETI - pop SP then pop PC. opeand field unused.
+111 not used
+
+relative jumps
+all PC-relative
+000 JNE/JNZ
+001 JEQ/JZ
+010 JNC/JLO
+011 JC/JHS
+100 JN
+101 JGE
+110 JL
+111 JMP
+
+twoop
+generally dest = src op dest
+mov doesnt fetch dest, cmp/bit dont write dest. all valid in 8 bit and 16 bit
+
+0100 MOV - dest = src
+0101 ADD - dest += src
+0110 ADDC - dest += src + C
+0111 SUBC - dest = dest - src + c (dest += ~src + C)
+1000 SUB - dest -= src
+1001 CMP - dest - src (set status only, dest not written)
+1010 DADD - dest += src + C, in BCD
+1011 BIT - dest & src (set status only)
+1100 BIC - dest &= ~src (status not set)
+1101 BIS - dest |= src (status not set)
+1110 XOR - dest ^= src
+1111 AND - dest &= src
+
+NOP implemented as virtual function, among others -
+NOP == MOV r3, r3
+POP dst == MOV @SP+, dst
+BR dst == MOV dst, PC
+RET == MOV @SP+, PC
+CLRC 1
+SETC 1
+CLRZ 2
+SETZ 2
+CLRN 4
+SETN 4
+DINT 8
+EINT 8
+
+RLA dst == ADD dst, dst
+RLC dst = ADDC dst, dst
+
+INV dst == XOR #-1, dst
+CLR dst == MOV #0, dst
+TST dst == CMP #0, dst
+
+DEC == SUB #1, dst
+DECD == SUB #2, dst
+INC == ADD #1, dst
+INCD == ADD #2, dst
+
+ADC dst == ADDC #0, dst
+DADC dst == DADD #0, dst
+SBC dst == SUBC #0, dst