Add Instructions for PIC Support #15

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opened 2023-09-15 23:24:59 +00:00 by InfernoDeity · 0 comments

InfernoDeity commented

2023-09-15 23:24:59 +00:00

Add the following instructions to the ISA, to support generation of PIC and PIE code. In all instructions PC is computed from the byte immediately following the last byte of the instruction

| Instruction Name | Mode | Effects |
|==================|======|========================|
| LRA | BBD |#1 <- #2 + imm #3 + PC|
| LDR | BBDH | #0 <- imm #4 [#2 + imm #3 + PC] |
| STR | BBDH | imm #4 [#2 + imm #3 + PC] |
| JMPR | D | Jumps tp #1 + PC |
| JALR | BBD | #0 <- PC Jumps to #1 + imm #2 + PC |
| JEQR | BBD | If #0 == #1 Jumps to imm #2 + PC |
| JNER | BBD | If #0 != #1 Jumps to imm #2 + PC |
| JLTR | BBD | If #0 < #1 (signed) Jumps to imm #2 + PC |
| JGTR | BBD | If #0 > #1 (signed) Jumps to imm #2 + PC |
| JLTUR | BBD | If #0 < #1 (unsigned) Jumps to imm #2 + PC |
| JGTUR | BBD | If #0 > #1 (unsigned) Jumps to imm #2 + PC |

Also add relaxed 8-bit and 32-bit version replacing the D operand with B or W respectively, for more compact codegen in common cases. Suggested mnemonics: _8 (IE. LRA8) and _32 (IE. LRA32)

Add the following instructions to the ISA, to support generation of PIC and PIE code. In all instructions `PC` is computed from the byte immediately following the last byte of the instruction | Instruction Name | Mode | Effects | |==================|======|========================| | LRA | BBD |`#1 <- #2 + imm #3 + PC`| | LDR | BBDH | `#0 <- imm #4 [#2 + imm #3 + PC]` | | STR | BBDH | `imm #4 [#2 + imm #3 + PC]` | | JMPR | D | Jumps tp `#1 + PC` | | JALR | BBD | `#0 <- PC` Jumps to `#1 + imm #2 + PC` | | JEQR | BBD | If `#0 == #1` Jumps to `imm #2 + PC` | | JNER | BBD | If `#0 != #1` Jumps to `imm #2 + PC` | | JLTR | BBD | If `#0 < #1` (signed) Jumps to `imm #2 + PC` | | JGTR | BBD | If `#0 > #1` (signed) Jumps to `imm #2 + PC` | | JLTUR | BBD | If `#0 < #1` (unsigned) Jumps to `imm #2 + PC` | | JGTUR | BBD | If `#0 > #1` (unsigned) Jumps to `imm #2 + PC` | Also add relaxed 8-bit and 32-bit version replacing the D operand with B or W respectively, for more compact codegen in common cases. Suggested mnemonics: `_8` (IE. `LRA8`) and `_32` (IE. `LRA32`)

Ghost closed this issue

2023-10-01 01:56:16 +00:00

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Reference: AbleOS/holey-bytes#15

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