Merge pull request #541 from eleanorLYJ/add-rv32e

Add support for the RV32E variant

Author: jserv

.ci/riscv-tests.sh

@@ -22,3 +22,7 @@ make ENABLE_EXT_M=1 ENABLE_EXT_A=1 ENABLE_EXT_F=1 ENABLE_EXT_C=1 \
 make arch-test RISCV_DEVICE=IMAFCZicsrZifencei $PARALLEL || exit 1
 make arch-test RISCV_DEVICE=FCZicsr $PARALLEL || exit 1
 make arch-test RISCV_DEVICE=IMZbaZbbZbcZbs $PARALLEL || exit 1
+
+make distclean
+make ENABLE_RV32E=1 ENABLE_FULL4G=1 $PARALLEL
+make arch-test RISCV_DEVICE=E $PARALLEL || exit 1

Makefile

@@ -127,6 +127,10 @@ endif
 ENABLE_EXT_C ?= 1
 $(call set-feature, EXT_C)
 
+# RV32E Base Integer Instruction Set
+ENABLE_RV32E ?= 0
+$(call set-feature, RV32E)
+
 # Control and Status Register (CSR)
 ENABLE_Zicsr ?= 1
 $(call set-feature, Zicsr)

README.md

@@ -24,7 +24,7 @@ a focus on efficiency and readability.
 
 Features:
 * Fast interpreter for executing the RV32 ISA
-* Comprehensive support for RV32I and M, A, F, C, Zba, Zbb, Zbc, Zbs extensions
+* Comprehensive support for RV32I, RV32E and M, A, F, C, Zba, Zbb, Zbc, Zbs extensions
 * Memory-efficient design
 * Built-in ELF loader
 * Implementation of commonly used newlib system calls
@@ -116,6 +116,7 @@ The image containing all the necessary tools for development and testing can be
 ### Customization
 
 `rv32emu` is configurable, and you can override the below variable(s) to fit your expectations:
+* `ENABLE_RV32E`: RV32E Base Integer Instruction Set
 * `ENABLE_EXT_M`: Standard Extension for Integer Multiplication and Division
 * `ENABLE_EXT_A`: Standard Extension for Atomic Instructions
 * `ENABLE_EXT_F`: Standard Extension for Single-Precision Floating Point Instructions
@@ -187,6 +188,7 @@ $ make arch-test RISCV_DEVICE=I
 Current progress of this emulator in riscv-arch-test (RV32):
 * Passed Tests
     - `I`: Base Integer Instruction Set
+    - `E`: RV32E Base Integer Instruction Set
     - `M`: Standard Extension for Integer Multiplication and Division
     - `A`: Standard Extension for Atomic Instructions
     - `F`: Standard Extension for Single-Precision Floating-Point

src/feature.h

@@ -27,6 +27,11 @@
 #define RV32_FEATURE_EXT_C 1
 #endif
 
+/* RV32E Base Integer Instruction Set */
+#ifndef RV32_FEATURE_RV32E
+#define RV32_FEATURE_RV32E 0
+#endif
+
 /* Control and Status Register (CSR) */
 #ifndef RV32_FEATURE_Zicsr
 #define RV32_FEATURE_Zicsr 1

src/riscv.c

@@ -769,10 +769,15 @@ void rv_reset(riscv_t *rv, riscv_word_t pc)
     rv->csr_mtvec = 0;
     rv->csr_cycle = 0;
     rv->csr_mstatus = 0;
-    rv->csr_misa |= MISA_SUPER | MISA_USER | MISA_I;
+    rv->csr_misa |= MISA_SUPER | MISA_USER;
     rv->csr_mvendorid = RV_MVENDORID;
     rv->csr_marchid = RV_MARCHID;
     rv->csr_mimpid = RV_MIMPID;
+#if !RV32_HAS(RV32E)
+    rv->csr_misa |= MISA_I;
+#else
+    rv->csr_misa |= MISA_E;
+#endif
 #if RV32_HAS(EXT_A)
     rv->csr_misa |= MISA_A;
 #endif

src/riscv.h

@@ -33,6 +33,7 @@
 extern "C" {
 #endif
 
+/* clang-format off */
 #define RV_REGS_LIST                                   \
     _(zero) /* hard-wired zero, ignoring any writes */ \
     _(ra)   /* return address */                       \
@@ -50,22 +51,25 @@ extern "C" {
     _(a3)                                              \
     _(a4)                                              \
     _(a5)                                              \
-    _(a6)                                              \
-    _(a7)                                              \
-    _(s2) /* saved register */                         \
-    _(s3)                                              \
-    _(s4)                                              \
-    _(s5)                                              \
-    _(s6)                                              \
-    _(s7)                                              \
-    _(s8)                                              \
-    _(s9)                                              \
-    _(s10)                                             \
-    _(s11)                                             \
-    _(t3) /* temporary register */                     \
-    _(t4)                                              \
-    _(t5)                                              \
-    _(t6)
+    IIF(RV32_HAS(RV32E))(,                             \
+        _(a6)                                          \
+        _(a7)                                          \
+        _(s2) /* saved register */                     \
+        _(s3)                                          \
+        _(s4)                                          \
+        _(s5)                                          \
+        _(s6)                                          \
+        _(s7)                                          \
+        _(s8)                                          \
+        _(s9)                                          \
+        _(s10)                                         \
+        _(s11)                                         \
+        _(t3) /* temporary register */                 \
+        _(t4)                                          \
+        _(t5)                                          \
+        _(t6)                                          \
+    )
+/* clang-format on */
 
 /* RISC-V registers (mnemonics, ABI names)
  *
@@ -117,6 +121,7 @@ enum SV32_PTE_PERM {
 #define MISA_SUPER (1 << ('S' - 'A'))
 #define MISA_USER (1 << ('U' - 'A'))
 #define MISA_I (1 << ('I' - 'A'))
+#define MISA_E (1 << ('E' - 'A'))
 #define MISA_M (1 << ('M' - 'A'))
 #define MISA_A (1 << ('A' - 'A'))
 #define MISA_F (1 << ('F' - 'A'))

src/syscall.c

@@ -466,8 +466,12 @@ static void syscall_sbi_rst(riscv_t *rv)
 
 void syscall_handler(riscv_t *rv)
 {
-    /* get the syscall number */
+/* get the syscall number */
+#if !RV32_HAS(RV32E)
     riscv_word_t syscall = rv_get_reg(rv, rv_reg_a7);
+#else
+    riscv_word_t syscall = rv_get_reg(rv, rv_reg_t0);
+#endif
 
     switch (syscall) { /* dispatch system call */
 #define _(name, number)     \

tests/arch-test-target/constants.py

@@ -8,7 +8,9 @@
 
 misa_A = (1 << 0)
 misa_C = (1 << 2)
+misa_E = (1 << 4)
 misa_F = (1 << 5)
+misa_I = (1 << 8)
 misa_M = (1 << 12)
 
 config_temp = '''[RISCOF]

tests/arch-test-target/rv32emu/env/model_test.h

@@ -13,10 +13,17 @@
 /* clang-format on */
 
 // RV_COMPLIANCE_HALT
+#ifndef RV32E
 #define RVMODEL_HALT \
     add a7, x0, 93;  \
     add a0, x0, 0;   \
     ecall
+#else
+#define RVMODEL_HALT \
+    add t0, x0, 93;  \
+    add a0, x0, 0;   \
+    ecall
+#endif
 
 #define RVMODEL_BOOT
 

tests/arch-test-target/rv32emu/riscof_rv32emu.py

@@ -86,7 +86,11 @@ def build(self, isa_yaml, platform_yaml):
         # will be useful in setting integer value in the compiler string (if not already hardcoded);
         self.xlen = ('64' if 64 in ispec['supported_xlen'] else '32')
 
-        self.compile_cmd = self.compile_cmd+' -mabi='+('lp64 ' if 64 in ispec['supported_xlen'] else 'ilp32 ')
+        if 'E' not in ispec['ISA']:
+            self.compile_cmd = self.compile_cmd+' -mabi='+('lp64 ' if 64 in ispec['supported_xlen'] else 'ilp32 ')
+        else:
+            self.compile_cmd = self.compile_cmd+' -mabi='+('lp64e ' if 64 in ispec['supported_xlen'] else 'ilp32e ')
+            self.compile_cmd += '-D RV32E '
 
     def runTests(self, testList):
         # Delete Makefile if it already exists.