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comparison backend.c @ 1703:49a52c737bf0

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Fix zero flag calculation in CPU DSL
author Michael Pavone <pavone@retrodev.com>
date Mon, 28 Jan 2019 19:24:04 -0800
parents d377d6037dd9
children 33ec5df77fac
comparison
equal deleted inserted replaced
1702:73ac2e59fa3f 1703:49a52c737bf0
127 return chunk->read_16(offset, context); 127 return chunk->read_16(offset, context);
128 } 128 }
129 return 0xFFFF; 129 return 0xFFFF;
130 } 130 }
131 131
132 uint8_t read_byte(uint32_t address, void **mem_pointers, cpu_options *opts, void *context)
133 {
134 memmap_chunk const *chunk = find_map_chunk(address, opts, 0, NULL);
135 if (!chunk) {
136 return 0xFF;
137 }
138 uint32_t offset = address & chunk->mask;
139 if (chunk->flags & MMAP_READ) {
140 uint8_t *base;
141 if (chunk->flags & MMAP_PTR_IDX) {
142 base = mem_pointers[chunk->ptr_index];
143 } else {
144 base = chunk->buffer;
145 }
146 if (base) {
147 if ((chunk->flags & MMAP_ONLY_ODD) || (chunk->flags & MMAP_ONLY_EVEN)) {
148 if (address & 1) {
149 if (chunk->flags & MMAP_ONLY_EVEN) {
150 return 0xFF;
151 }
152 } else if (chunk->flags & MMAP_ONLY_ODD) {
153 return 0xFF;
154 }
155 offset /= 2;
156 }
157 return base[offset];
158 }
159 }
160 if ((!(chunk->flags & MMAP_READ) || (chunk->flags & MMAP_FUNC_NULL)) && chunk->read_8) {
161 return chunk->read_8(offset, context);
162 }
163 return 0xFF;
164 }
165
166 void write_byte(uint32_t address, uint8_t value, void **mem_pointers, cpu_options *opts, void *context)
167 {
168 memmap_chunk const *chunk = find_map_chunk(address, opts, 0, NULL);
169 if (!chunk) {
170 return;
171 }
172 uint32_t offset = address & chunk->mask;
173 if (chunk->flags & MMAP_WRITE) {
174 uint8_t *base;
175 if (chunk->flags & MMAP_PTR_IDX) {
176 base = mem_pointers[chunk->ptr_index];
177 } else {
178 base = chunk->buffer;
179 }
180 if (base) {
181 if ((chunk->flags & MMAP_ONLY_ODD) || (chunk->flags & MMAP_ONLY_EVEN)) {
182 if (address & 1) {
183 if (chunk->flags & MMAP_ONLY_EVEN) {
184 return;
185 }
186 } else if (chunk->flags & MMAP_ONLY_ODD) {
187 return;
188 }
189 offset /= 2;
190 }
191 base[offset] = value;
192 }
193 }
194 if ((!(chunk->flags & MMAP_WRITE) || (chunk->flags & MMAP_FUNC_NULL)) && chunk->write_8) {
195 chunk->write_8(offset, context, value);
196 }
197 }
198
132 uint32_t chunk_size(cpu_options *opts, memmap_chunk const *chunk) 199 uint32_t chunk_size(cpu_options *opts, memmap_chunk const *chunk)
133 { 200 {
134 if (chunk->mask == opts->address_mask) { 201 if (chunk->mask == opts->address_mask) {
135 return chunk->end - chunk->start; 202 return chunk->end - chunk->start;
136 } else { 203 } else {