546 lines
9.5 KiB
ArmAsm
546 lines
9.5 KiB
ArmAsm
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.include "6502def.s"
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// 将 6502 PC 地址转换为 ROM 偏移地址
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.macro encodePC
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and r1, m6502_pc, #0xE000 // r9 & 0xE000
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add r2, globalptr,#memmap_tbl // 加载内存映射表地址到 r2
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lsr r0, r1, #11 // >>11位
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ldr r0, [r2, r0] // 从 r2 + r0 加载数据到 r0
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str r0, [globalptr,#lastbank] // 保存当前 bank 偏移
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add m6502_pc, m6502_pc, r0 // m6502_pc += r0
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.endm
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// 打包 6502 标志到 r0
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.macro encodeP extra
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and r0, cycles, #CYC_V+CYC_D+CYC_I+CYC_C // CYC_V+CYC_D+CYC_I+CYC_C
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tst m6502_nz, #0x80000000 // PSR_N
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IT NE
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orrne r0, r0, #N // 设置 N 标志
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tst m6502_nz, #0xFF // Z 标志
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IT EQ
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orreq r0, r0, #Z // 设置 Z 标志
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orr r0, r0, #\extra // 添加额外标志 (B/R)
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.endm
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// 解包 r0 中的 6502 标志
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.macro decodeP
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bic cycles,cycles,#CYC_V+CYC_D+CYC_I+CYC_C // 清除 CYC_V+CYC_D+CYC_I+CYC_C
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and r1, r0, #V+D+I+C // 提取 V/D/I/C 标志
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orr cycles,cycles,r1 // 写入 cycles
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bic m6502_nz, r0, #0xFD // r0 is signed
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eor m6502_nz, m6502_nz, #Z // 反转 Z 位
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.endm
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// 获取下一条指令并执行
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.macro fetch count
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ldr r0, [r10,#clocksh]
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add r0, r0, \count
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str r0, [globalptr,#clocksh]
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ldr r1, [globalptr,#opz]
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subs cycles, cycles, \count*256
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ITT PL
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ldrbpl r0, [m6502_pc], #1
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ldrpl pc, [r1, r0, lsl #2]
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ldr pc, [globalptr,#nexttimeout]
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.endm
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// 同上，但考虑 Carry 位
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.macro fetch_c count
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ldr r0, [globalptr,#clocksh]
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add r0, r0, \count
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str r0, [globalptr,#clocksh]
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ldr r1, [globalptr,#opz]
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sbcs cycles, cycles, \count*256
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ITT PL
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ldrbpl r0, [m6502_pc], #1
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ldrpl pc, [r1, r0, lsl #2]
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ldr pc, [globalptr,#nexttimeout]
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.endm
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// 清除周期标志
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.macro clearcycles
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and cycles,cycles,#CYC_MASK // CYC_MASK
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.endm
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// 绝对地址读取
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.macro readmemabs
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and r1, addy, #0xE000
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adr lr, 0f
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lsr r1, r1, #11
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ldr pc, [m6502_rmem, r1]
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0:
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.endm
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// 零页读取
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.macro readmemzp
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ldrb r0, [cpu_zpage, addy]
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.endm
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// 零页索引读取（带高位）
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.macro readmemzpi
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lsr r0, addy, #24
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ldrb r0, [cpu_zpage, r0]
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.endm
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// RAM 读取并设置 NZ
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.macro readmemzps
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ldrsb m6502_nz, [cpu_zpage,addy]
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.endm
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// 立即数读取
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.macro readmemimm
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ldrb r0, [m6502_pc], #1
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.endm
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// 立即数读取并设置 NZ
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.macro readmemimms
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ldrsb m6502_nz, [m6502_pc], #1
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.endm
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// 根据类型选择读取方式
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.macro readmem
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.if _type == _ABS
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readmemabs
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.elseif _type == _ZP
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readmemzp
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.elseif _type == _ZPI
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readmemzpi
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.elseif _type == _IMM
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readmemimm
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.endif
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.endm
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// 带符号扩展的读取
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.macro readmems
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.if _type == _ABS
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readmemabs
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orr m6502_nz, r0, r0, lsl #24
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.elseif _type == _ZP
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readmemzps
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.elseif _type == _IMM
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readmemimms
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.endif
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.endm
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// 绝对地址写入
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.macro writememabs
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and r1, addy, #0xE000
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@ ldr r2, =writemem_tbl
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@ add r2, globalptr
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add r2, globalptr,#writemem_tbl
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adr lr, 0f
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lsr r1, r1, #11
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ldr pc, [r2, r1]
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0:
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.endm
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// 零页写入
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.macro writememzp
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strb r0, [cpu_zpage,addy]
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.endm
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// 零页索引写入
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.macro writememzpi
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lsr r1, addy, #24
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strb r0, [cpu_zpage, r1]
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.endm
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// 根据类型选择写入方式
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.macro writemem
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.if _type == _ABS
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writememabs
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.elseif _type == _ZP
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writememzp
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.elseif _type == _ZPI
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writememzpi
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.endif
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.endm
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// 16位压栈
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.macro push16
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mov r1, r0, lsr #8
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ldr r2, [globalptr,#m6502_s]
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strb r1, [r2], #-1
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orr r2, r2, #0x100
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strb r0, [r2], #-1
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strb r2, [globalptr,#m6502_s]
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.endm
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// 8位压栈
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.macro push8 x
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ldr r2, [globalptr,#m6502_s]
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strb \x, [r2], #-1
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strb r2, [globalptr,#m6502_s]
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.endm
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// 16位弹栈
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.macro pop16
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ldrb r2, [globalptr,#m6502_s]
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add r2, r2, #2
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strb r2, [globalptr,#m6502_s]
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ldr r2, [globalptr,#m6502_s]
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ldrb r0, [r2], #-1
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orr r2, r2, #0x100
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ldrb m6502_pc, [r2]
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orr m6502_pc, m6502_pc, r0, lsl #8
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.endm
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// 8位弹栈（带符号扩展）
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.macro pop8 x
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ldrb r2, [globalptr,#m6502_s]
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add r2, r2, #1
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strb r2, [globalptr,#m6502_s]
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orr r2, r2, #0x100
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ldrsb \x, [cpu_zpage, r2]
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.endm
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// 定义寻址模式常量
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.equ _IMM, 1
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.equ _ZP, 2
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.equ _ZPI, 3
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.equ _ABS, 4
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// 绝对寻址
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.macro doABS
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.set _type, _ABS
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ldrb addy, [m6502_pc], #1
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ldrb r0, [m6502_pc], #1
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orr addy, addy, r0, lsl #8
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.endm
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// X寄存器绝对索引
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.macro doAIX
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.set _type, _ABS
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ldrb addy, [m6502_pc], #1
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ldrb r0, [m6502_pc], #1
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orr addy, addy, r0, lsl #8
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add addy, addy, m6502_x, lsr #24
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.endm
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// Y寄存器绝对索引
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.macro doAIY
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.set _type, _ABS
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ldrb addy, [m6502_pc], #1
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ldrb r0, [m6502_pc], #1
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orr addy, addy, r0, lsl #8
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add addy, addy, m6502_y, lsr #24
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.endm
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// 立即数寻址
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.macro doIMM
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.set _type, _IMM
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.endm
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// X寄存器间接寻址
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.macro doIIX
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.set _type, _ABS
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ldrb r0, [m6502_pc], #1
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add r0, m6502_x, r0, lsl #24
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lsr addy, r0, #24
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ldrb addy, [cpu_zpage, addy]
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add r0, r0, #0x01000000
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lsr r1, r0, #24
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ldrb r1, [cpu_zpage, r1]
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orr addy, addy, r1, lsl #8
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.endm
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// Y寄存器间接寻址
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.macro doIIY
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.set _type, _ABS
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ldrb r0, [m6502_pc], #1
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ldrb addy, [r0,cpu_zpage]
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add r0, r0, cpu_zpage
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ldrb r1, [r0, #1]
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orr addy, addy, r1, lsl #8
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add addy, addy, m6502_y, lsr #24
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.endm
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// 零页间接寻址
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.macro doZPI
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.set _type, _ABS
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ldrb r0, [m6502_pc], #1
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ldrb addy, [r0,cpu_zpage]
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add r0, r0, cpu_zpage
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ldrb r1, [r0, #1]
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orr addy, addy, r1, lsl #8
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.endm
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// 零页寻址
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.macro doZ
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.set _type, _ZP
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ldrb addy, [m6502_pc], #1
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.endm
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// 零页双字节寻址（用于 bbr/bbs）
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.macro doZ2
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.set _type, _ZP
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ldrb addy, [m6502_pc], #2
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.endm
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// 零页X索引
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.macro doZIX
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.set _type, _ZP
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ldrb addy, [m6502_pc], #1
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add addy, addy, m6502_x, lsr #24
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and addy, addy, #0xff
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.endm
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// 零页X索引（带左移）
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.macro doZIXf
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.set _type, _ZPI
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ldrb addy, [m6502_pc], #1
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add addy, m6502_x, addy, lsl #24
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.endm
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// 零页Y索引
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.macro doZIY
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.set _type, _ZP
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ldrb addy, [m6502_pc], #1
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add addy, addy, m6502_y, lsr #24
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and addy, addy, #0xff
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.endm
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// 零页Y索引（带左移）
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.macro doZIYf
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.set _type, _ZPI
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ldrb addy, [m6502_pc], #1
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add addy, m6502_y, addy, lsl #24
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.endm
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// ADC 操作
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.macro opADC
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readmem
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movs r1, cycles, lsr #1
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IT CS
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subcs r0, r0, #0x00000100
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adcs m6502_a, m6502_a, r0, ror #8
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mov m6502_nz, m6502_a, asr #24
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orr cycles, cycles, #CYC_C+CYC_V
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IT VC
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bicvc cycles, cycles, #CYC_V
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.endm
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// AND 操作
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.macro opAND
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readmem
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and m6502_a, m6502_a, r0, lsl #24
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mov m6502_nz, m6502_a, asr #24
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.endm
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// ASL 操作
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.macro opASL
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readmem
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add r0, r0, r0
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orrs m6502_nz, r0, r0, lsl #24
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orr cycles, cycles, #CYC_C
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writemem
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.endm
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// BIT 操作
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.macro opBIT
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readmem
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bic cycles, cycles, #CYC_V
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tst r0, #V
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IT NE
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orrne cycles, cycles, #CYC_V
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and m6502_nz, r0, m6502_a, lsr #24
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orr m6502_nz, m6502_nz, r0, lsl #24
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.endm
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// 比较操作
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.macro opCOMP x
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readmem
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subs m6502_nz, \x, r0, lsl #24
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mov m6502_nz, m6502_nz, asr #24
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orr cycles, cycles, #CYC_C
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.endm
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// 减一操作
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.macro opDEC
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readmem
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sub r0, r0, #1
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orr m6502_nz, r0, r0, lsl #24
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writemem
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.endm
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// 异或操作
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.macro opEOR
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readmem
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eor m6502_a, m6502_a, r0, lsl #24
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mov m6502_nz, m6502_a, asr #24
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.endm
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// 加一操作
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.macro opINC
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readmem
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add r0, r0, #1
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orr m6502_nz, r0, r0, lsl #24
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writemem
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.endm
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// 加载操作
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.macro opLOAD x
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readmems
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mov \x, m6502_nz, lsl #24
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.endm
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// 逻辑右移
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.macro opLSR
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.if _type == _ABS
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readmemabs
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movs r0, r0, lsr #1
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orr cycles, cycles, #CYC_C
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mov m6502_nz, r0
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writememabs
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.elseif _type == _ZP
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ldrb m6502_nz, [cpu_zpage, addy]
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movs m6502_nz, m6502_nz, lsr #1
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orr cycles, cycles, #CYC_C
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strb m6502_nz, [cpu_zpage, addy]
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.elseif _type == _ZPI
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lsr m6502_nz, addy, #24
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ldrb m6502_nz, [cpu_zpage, m6502_nz]
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movs m6502_nz, m6502_nz, lsr #1
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orr cycles, cycles, #CYC_C
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lsr r1, addy, #24
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strb m6502_nz, [cpu_zpage, r1]
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.endif
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.endm
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// OR 操作
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.macro opORA
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readmem
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orr m6502_a, m6502_a, r0, lsl #24
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mov m6502_nz, m6502_a, asr #24
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.endm
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// 循环左移
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.macro opROL
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readmem
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movs cycles, cycles, lsr #1
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adc r0, r0, r0
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orrs m6502_nz, r0, r0, lsl #24
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adc cycles, cycles, cycles
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writemem
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.endm
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// 循环右移
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.macro opROR
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readmem
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movs cycles, cycles, lsr #1
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IT CS
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orrcs r0, r0, #0x100
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movs r0, r0, lsr #1
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orr m6502_nz, r0, r0, lsl #24
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adc cycles, cycles, cycles
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writemem
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.endm
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// 带进位减法
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.macro opSBC
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readmem
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movs r1, cycles, lsr #1
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sbcs m6502_a, m6502_a, r0, lsl #24
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and m6502_a, m6502_a, #0xff000000
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mov m6502_nz, m6502_a, asr #24
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orr cycles, cycles, #CYC_C+CYC_V
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IT VC
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bicvc cycles, cycles, #CYC_V
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.endm
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.macro opSTORE x
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mov r0, \x, lsr #24
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writemem
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.endm
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@ .global main
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@ .type main, %function
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@ mian:
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@ encodePC
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@ encodeP (B+R)
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@ encodeP (R)
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@ decodeP
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@ fetch 10
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@ fetch_c 10
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@ clearcycles
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@ readmemabs
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@ readmemzp
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@ readmemzpi
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@ readmemzps
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@ readmemimm
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@ readmemimms
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@ readmem
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@ readmems
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@ writememabs
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@ writememzp
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@ writememzpi
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@ writemem
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@ push16
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@ push8 r0
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@ pop16
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@ pop8 r0
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@ doABS
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@ doAIX
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@ doAIY
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@ doIMM
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@ doIIX
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@ doIIY
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@ doZPI
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@ doZ
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@ doZ2
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@ doZIX
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@ doZIXf
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@ doZIY
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@ doZIYf
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@ opADC
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@ opAND
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@ opASL
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@ opBIT
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@ opCOMP r5
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@ opDEC
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@ opEOR
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@ opINC
|
||
@ opLOAD r5
|
||
@ opLSR
|
||
@ opORA
|
||
@ opROL
|
||
@ opROR
|
||
@ opSBC
|
||
@ opSTORE r5
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|